diff --git a/src/Aufgabe1_Kellerautomat.java b/src/Aufgabe1_Kellerautomat.java
index 6473ef5..41ff12c 100644
--- a/src/Aufgabe1_Kellerautomat.java
+++ b/src/Aufgabe1_Kellerautomat.java
@@ -1,4 +1,7 @@
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
 
 public class Aufgabe1_Kellerautomat {
     private static String[] words = {"ZZO", "ZZOZZOO", "ZZZOO", "ZZOO", "ZZOZZO", "ZOZ"};
@@ -10,17 +13,21 @@ public class Aufgabe1_Kellerautomat {
     }
 
     public static boolean calculate(String word) {
-        char[] wordChars = word.toCharArray();
+        List<Character> wordChars = new ArrayList<>();
+        for (char symbol : word.toCharArray()) {
+            wordChars.add(symbol);
+        }
         ArrayList<Character> stack = new ArrayList<>();
         stack.add('$');
 
         int state = 0; //case 0 - 5 = q0 - q5, case -1 = Abfallzustand
 
-        for (char symbol : wordChars) {
+        while (wordChars.size() > 0 || state >= 3) {
+            char symbol;
             Character stackSymbol = stack.remove(stack.size() - 1);
             switch (state) {
                 case 0:
-                    if (symbol == 'Z' && stackSymbol == '$') {
+                    if (wordChars.remove(0) == 'Z' && stackSymbol == '$') {
                         stack.add('$');
                         stack.add('Z');
                         state = 1;
@@ -30,7 +37,7 @@ public class Aufgabe1_Kellerautomat {
                     }
                     break;
                 case 1:
-                    if (symbol == 'Z' && stackSymbol == 'Z') {
+                    if (wordChars.remove(0) == 'Z' && stackSymbol == 'Z') {
                         stack.add('Z');
                         stack.add('Z');
                         state = 2;
@@ -40,6 +47,7 @@ public class Aufgabe1_Kellerautomat {
                     }
                     break;
                 case 2:
+                    symbol = wordChars.remove(0);
                     if (symbol == 'O' && stackSymbol == 'Z') {
                         state = 3;
                     } else if (symbol == 'Z' && stackSymbol == 'Z') {
@@ -56,42 +64,53 @@ public class Aufgabe1_Kellerautomat {
                     }
                     break;
                 case 3:
-                    if (symbol == 'O' && stackSymbol == 'Z') {
-                        state = 3;
-                    } else if (symbol == 'Z' && stackSymbol == 'Z') {
+                    if (stackSymbol == 'Z') {
                         stack.add('Z');
-                        stack.add('Z');
-                        state = 2;
+                        state = 4;
                     } else {
                         dontAccept(word);
                         return false;
                     }
                     break;
+                case 4:
+                    if (wordChars.size() > 0) {
+                        symbol = wordChars.remove(0);
+                        if (symbol == 'Z' && stackSymbol == 'Z') {
+                            stack.add('Z');
+                            stack.add('Z');
+                            state = 2;
+                        } else if (symbol == 'O' && stackSymbol == 'Z') {
+                            state = 3;
+                        } else {
+                            dontAccept(word);
+                            return false;
+                        }
+                    } else {
+                        if (stackSymbol == 'Z') {
+                            state = 5;
+                        } else {
+                            dontAccept(word);
+                            return false;
+                        }
+                    }
+                    break;
+                case 5:
+                    if (stackSymbol == '$') {
+                        stack.add('$');
+                        state = 6;
+                    } else {
+                        dontAccept(word);
+                        return false;
+                    }
+                    break;
+                case 6:
+                    accept(word);
+                    return true;
+
             }
         }
-
-        if (state == 3 && stack.size() >= 1 && stack.remove(stack.size() - 1) == 'Z') {
-            state = 4;
-        } else {
-            dontAccept(word);
-            return false;
-        }
-
-        if (state == 4 && stack.size() >= 1 && stack.remove(stack.size() - 1) == '$') {
-            state = 5;
-        } else {
-            dontAccept(word);
-            return false;
-        }
-
-        if (state == 5) {
-            accept(word);
-            return true;
-        } else {
-            dontAccept(word);
-            return false;
-        }
-
+        dontAccept(word);
+        return false;
     }
 
     private static void dontAccept(String word) {
diff --git a/src/Kellerautomat.java b/src/Kellerautomat.java
new file mode 100644
index 0000000..913c25f
--- /dev/null
+++ b/src/Kellerautomat.java
@@ -0,0 +1,128 @@
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+public class Kellerautomat {
+    private static String[] words = {"ZZO", "ZZOZZOO", "ZZZOO", "ZZOO", "ZZOZZO", "ZOZ"};
+
+    public static void main(String[] args) {
+        for (String word : words) {
+            calculate(word);
+        }
+    }
+
+    public static boolean calculate(String word) {
+        List<Character> wordChars = new ArrayList<>();
+        for (char symbol : word.toCharArray()) {
+            wordChars.add(symbol);
+        }
+        ArrayList<Character> stack = new ArrayList<>();
+        stack.add('$');
+
+        int state = 0; //case 0 - 5 = q0 - q5, case -1 = Abfallzustand
+
+        while (wordChars.size() > 0 || state >= 3) {
+            char symbol;
+            Character stackSymbol = stack.remove(stack.size() - 1);
+            switch (state) {
+                case 0:
+                    if (wordChars.remove(0) == 'Z' && stackSymbol == '$') {
+                        stack.add('$');
+                        stack.add('Z');
+                        state = 1;
+                    } else {
+                        dontAccept(word);
+                        return false;
+                    }
+                    break;
+                case 1:
+                    if (wordChars.remove(0) == 'Z' && stackSymbol == 'Z') {
+                        stack.add('Z');
+                        stack.add('Z');
+                        state = 2;
+                    } else {
+                        dontAccept(word);
+                        return false;
+                    }
+                    break;
+                case 2:
+                    symbol = wordChars.remove(0);
+                    if (symbol == 'O' && stackSymbol == 'Z') {
+                        state = 3;
+                    } else if (symbol == 'Z' && stackSymbol == 'Z') {
+                        stack.add('Z');
+                        stack.add('Z');
+                        state = 2;
+                    } else if (symbol == 'Z' && stackSymbol == '$') {
+                        stack.add('$');
+                        stack.add('Z');
+                        state = 2;
+                    } else {
+                        dontAccept(word);
+                        return false;
+                    }
+                    break;
+                case 3:
+                    if (stackSymbol == 'Z') {
+                        stack.add('Z');
+                        state = 4;
+                    } else {
+                        dontAccept(word);
+                        return false;
+                    }
+                    break;
+                case 4:
+                    if (wordChars.size() > 0) {
+                        symbol = wordChars.remove(0);
+                        if (symbol == 'Z' && stackSymbol == 'Z') {
+                            stack.add('Z');
+                            stack.add('Z');
+                            state = 2;
+                        } else if (symbol == 'O' && stackSymbol == 'Z') {
+                            state = 3;
+                        } else {
+                            dontAccept(word);
+                            return false;
+                        }
+                    } else {
+                        if (stackSymbol == 'Z') {
+                            state = 5;
+                        } else {
+                            dontAccept(word);
+                            return false;
+                        }
+                    }
+                    break;
+                case 5:
+                    if (stackSymbol == '$') {
+                        stack.add('$');
+                        state = 6;
+                    } else {
+                        dontAccept(word);
+                        return false;
+                    }
+                    break;
+                case 6:
+                    accept(word);
+                    return true;
+
+            }
+        }
+        dontAccept(word);
+        return false;
+    }
+
+    private static void dontAccept(String word) {
+        System.out.println("Word: " + word  + "\nnot accepted");
+    }
+
+    private static void accept(String word) {
+        System.out.println("Word: " + word  + "\naccepted ");
+    }
+
+    private static boolean isOperator(char symbol){
+        return symbol == '+' || symbol == '*';
+    }
+
+}