struct Node {
  int value;
  Node* left;
  Node* right;

  Node(int value) : value(value) {}
};

int sum_tree_leaves(Node* root) {
}

int main() {
  Node* root = new Node(5);
  root->left = new Node(4);
  root->right = new Node(2);
  root->left->left = new Node(1);
  root->left->right = new Node(6);
  root->right->right = new Node(3);
  root->right->right->left = new Node(7);

  /*
      5
     / \
    4   2
   / \   \
  1   6   3
         /
        7
  */

  std::cout << "Result: " << sum_tree_leaves(root);
}