diff --git a/src/UE07_221024_RegExp3/ChemicalEquations.java b/src/UE07_221024_RegExp3/ChemicalEquations.java
new file mode 100644
index 0000000..79ae165
--- /dev/null
+++ b/src/UE07_221024_RegExp3/ChemicalEquations.java
@@ -0,0 +1,68 @@
+package UE07_221024_RegExp3;
+
+import java.util.Map;
+import java.util.Scanner;
+import java.util.TreeMap;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class ChemicalEquations {
+    public static void main(String[] args) {
+/*
+HCl + Na -> NaCl + H2
+2 HCl + 2 Na -> 2 NaCl + H2
+12 CO2 + 6 H2O -> 2 C6H12O6 + 12 O2
+N2 + H2 -> NH3
+2 KClO3 -> 2 KCl + 3 O2
+CaCO3 + HCl -> CaCl2 + H2O + CO2
+C3H8 + 5 O2 -> 3 CO2 + 4 H2O
+2 Ag + O2 -> 2 AgO
+Fe2O3 + 3 CO -> 2 Fe + 3 CO2
+Mg + O2 -> MgO
+*/
+        Scanner scanner = new Scanner(System.in);
+        String input;
+        while (!(input = scanner.nextLine()).equals("end"))
+            System.out.println((analyze(input) ? "formally correct" : "incorrect") + "\n");
+    }
+
+    public static boolean analyze(String formular) {
+        String[] s = formular.split("->");
+        try {
+            Map<String, Integer> first = mapElements(s[0]);
+            Map<String, Integer> second = mapElements(s[1]);
+            if (first.isEmpty() || second.isEmpty()) return false;
+            return first.equals(second);
+        } catch (Exception e) {
+            return false;
+        }
+    }
+
+    public static Map<String, Integer> mapElements(String s) {
+        Map<String, Integer> elements = new TreeMap<>();
+        String[] parts = s.replaceAll(" ", "").split("\\+");
+        Pattern pattern = Pattern.compile("\\d*([A-Z][a-z]?|[A-Z])(\\d*)");
+        Pattern patternC = Pattern.compile("^(\\d+)[a-zA-Z]+");
+        int coefficient;
+        int number;
+        for (String part : parts) {
+            coefficient = 1;
+            Matcher matcher = pattern.matcher(part);
+            Matcher matcherC = patternC.matcher(part);
+            while (matcherC.find()) try {
+                coefficient = Integer.parseInt(matcherC.group(1));
+            } catch (Exception e) {
+                coefficient = 1;
+            }
+            while (matcher.find()) {
+                try {
+                    number = Integer.parseInt(matcher.group(2));
+                } catch (Exception e) {
+                    number = 1;
+                }
+                elements.put(matcher.group(1), elements.getOrDefault(matcher.group(1), 0) + (number * coefficient));
+            }
+        }
+        return elements;
+    }
+}
diff --git a/src/UE09_191124_Rekursion2/UE09_Rekursion2.java b/src/UE09_191124_Rekursion2/UE09_Rekursion2.java
new file mode 100644
index 0000000..3ea016f
--- /dev/null
+++ b/src/UE09_191124_Rekursion2/UE09_Rekursion2.java
@@ -0,0 +1,57 @@
+package UE09_191124_Rekursion2;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+
+public class UE09_Rekursion2 {
+    public static void main(String[] args) {
+//        int[][] file1 = readFile("src/UE09_191124_Rekursion2/UE09_triangle1.txt");
+//        int[][] file2 = readFile("src/UE09_191124_Rekursion2/UE09_triangle2.txt");
+//        int[][] file3 = readFile("src/UE09_191124_Rekursion2/UE09_triangle.txt");
+//        System.out.println("\n" + maxTotalRekursion(file1, 0, 0));
+//        System.out.println("\n" + maxTotalRekursion(file2, 0, 0));
+//        System.out.println("\n" + maxTotalRekursion(file3, 0, 0)); //Braucht ewig lange, da File sehr groß
+        System.out.println(collatz());
+    }
+
+    public static int[][] readFile(String file) {
+        try {
+            List<String> lines = Files.readAllLines(Path.of(file));
+            int[][] output = new int[lines.size()][];
+            for (int i = 0; i < output.length; i++) {
+                String[] line = lines.get(i).trim().split(" ");
+                output[i] = new int[line.length];
+                for (int j = 0; j < line.length; j++) output[i][j] = Integer.parseInt(line[j]);
+            }
+            return output;
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static long maxTotalRekursion(int[][] input, int x, int y) {
+        return (x >= input.length - 1) ? input[x][y] : Long.max(maxTotalRekursion(input, x + 1, y), maxTotalRekursion(input, x + 1, y + 1)) + input[x][y];
+    }
+
+    public static long collatz() {
+        long startingNumber = 0, maxLength = 0;
+        for (int i = 1; i < 1000000; i++) {
+            long length = longestCollatzSequence(new ArrayList<>(), i).size();
+            if (length > maxLength) {
+                maxLength = length;
+                startingNumber = i;
+            }
+        }
+        return startingNumber;
+    }
+
+    public static List<Long> longestCollatzSequence(List<Long> l, long n) {
+        if (n == 1) return l;
+        l.add(n);
+        n = ((n & 1) == 0) ? (n / 2) : (3 * n + 1);
+        return longestCollatzSequence(l, n);
+    }
+}
diff --git a/src/UE09_191124_Rekursion2/UE09_triangle1.txt b/src/UE09_191124_Rekursion2/UE09_triangle1.txt
new file mode 100644
index 0000000..ac777c8
--- /dev/null
+++ b/src/UE09_191124_Rekursion2/UE09_triangle1.txt
@@ -0,0 +1,4 @@
+3
+7 4
+2 4 6
+8 5 9 3
\ No newline at end of file
diff --git a/src/UE09_191124_Rekursion2/UE09_triangle2.txt b/src/UE09_191124_Rekursion2/UE09_triangle2.txt
new file mode 100644
index 0000000..bc0ed83
--- /dev/null
+++ b/src/UE09_191124_Rekursion2/UE09_triangle2.txt
@@ -0,0 +1,15 @@
+75
+95 64
+17 47 82
+18 35 87 10
+20 04 82 47 65
+19 01 23 75 03 34
+88 02 77 73 07 63 67
+99 65 04 28 06 16 70 92
+41 41 26 56 83 40 80 70 33
+41 48 72 33 47 32 37 16 94 29
+53 71 44 65 25 43 91 52 97 51 14
+70 11 33 28 77 73 17 78 39 68 17 57
+91 71 52 38 17 14 91 43 58 50 27 29 48
+63 66 04 68 89 53 67 30 73 16 69 87 40 31
+04 62 98 27 23 09 70 98 73 93 38 53 60 04 23
\ No newline at end of file