diff --git a/src/main.c b/src/main.c
index b55d6c9..a86ee0f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,7 +1,174 @@
-#include "greet.h"
 #include <stdio.h>
+#include <stdlib.h>
+
+#include "greet.h"
+
+struct Node {
+    int data;
+    struct Node *left, *right;
+};
+typedef struct Node Node;
+
+struct Tree {
+    Node *root;
+};
+typedef struct Tree Tree;
+
+int tree_insert(Tree *tree, int data) {
+    Node *node = malloc(sizeof(Node));
+    node->data = data;
+    node->left = NULL;
+    node->right = NULL;
+
+    if (tree->root == NULL) {
+        tree->root = node;
+        return 0;
+    }
+
+    Node *current = tree->root;
+    while (current != NULL) {
+        if (data < current->data) {
+            if (current->left == NULL) {
+                current->left = node;
+                return 0;
+            }
+            current = current->left;
+        } else {
+            if (current->right == NULL) {
+                current->right = node;
+                return 0;
+            }
+            current = current->right;
+        }
+    }
+    return 1;
+}
+
+int tree_remove(Tree *tree, int data) {
+    if (tree->root == NULL) {
+        return 1;
+    }
+
+    Node *current = tree->root;
+    Node *parent = NULL;
+    while (current != NULL) {
+        if (data < current->data) {
+            parent = current;
+            current = current->left;
+        } else if (data > current->data) {
+            parent = current;
+            current = current->right;
+        } else {
+            if (current->left == NULL && current->right == NULL) {
+                if (parent == NULL) {
+                    tree->root = NULL;
+                } else if (parent->left == current) {
+                    parent->left = NULL;
+                } else {
+                    parent->right = NULL;
+                }
+                free(current);
+                return 0;
+            } else if (current->left == NULL) {
+                if (parent == NULL) {
+                    tree->root = current->right;
+                } else if (parent->left == current) {
+                    parent->left = current->right;
+                } else {
+                    parent->right = current->right;
+                }
+                free(current);
+                return 0;
+            } else if (current->right == NULL) {
+                if (parent == NULL) {
+                    tree->root = current->left;
+                } else if (parent->left == current) {
+                    parent->left = current->left;
+                } else {
+                    parent->right = current->left;
+                }
+                free(current);
+                return 0;
+            } else {
+                Node *successor = current->right;
+                Node *successor_parent = current;
+                while (successor->left != NULL) {
+                    successor_parent = successor;
+                    successor = successor->left;
+                }
+                current->data = successor->data;
+                if (successor_parent->left == successor) {
+                    successor_parent->left = successor->right;
+                } else {
+                    successor_parent->right = successor->right;
+                }
+                free(successor);
+                return 0;
+            }
+        }
+    }
+    return 1;
+}
+
+int tree_clear(Tree *tree) {
+    if (tree->root == NULL) {
+        return 0;
+    }
+
+    Node *current = tree->root;
+    while (current != NULL) {
+        if (current->left != NULL) {
+            current = current->left;
+        } else if (current->right != NULL) {
+            current = current->right;
+        } else {
+            Node *parent = current;
+            current = NULL;
+            if (parent == tree->root) {
+                tree->root = NULL;
+            } else if (parent->left != NULL) {
+                parent->left = NULL;
+            } else {
+                parent->right = NULL;
+            }
+            free(parent);
+        }
+    }
+    return 0;
+}
+
+int tree_size(Tree *tree) {
+    if (tree->root == NULL) {
+        return 0;
+    }
+
+    int size = 0;
+    Node *current = tree->root;
+    while (current != NULL) {
+        size++;
+        if (current->left != NULL) {
+            current = current->left;
+        } else if (current->right != NULL) {
+            current = current->right;
+        } else {
+            current = NULL;
+        }
+    }
+    return size;
+}
 
 int main(void) {
-  greet("Template");
-  return 0;
+    Tree tree = {NULL};
+    printf("Tree size: %d\n", tree_size(&tree));
+    tree_insert(&tree, 1);
+    tree_insert(&tree, 2);
+    tree_insert(&tree, 3);
+    printf("Tree size: %d\n", tree_size(&tree));
+    tree_remove(&tree, 2);
+    printf("Tree size: %d\n", tree_size(&tree));
+    tree_clear(&tree);
+    printf("Tree size: %d\n", tree_size(&tree));
+
+    greet("Template");
+    return 0;
 }
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