class Solution {
public:
    int ans=0;
    int sumNumbers(TreeNode* root) {
        if(root)dfs(root, 0);
        return ans;
    }
    void dfs(TreeNode* root, int number)
    {
        number=number*10+root->val;
        if(!root->left&&!root->right)ans+=number;
        if(root->left)dfs(root->left, number);
        if(root->right)dfs(root->right, number);
    }
};