class Solution {
public:
    int DFS(TreeNode *root,int presum)
    {
        if(root==NULL)return 0;
        int sum=presum*10+root->val;
        if(root->left==NULL&&root->right==NULL)return sum;
        return DFS(root->left,sum)+DFS(root->right,sum);


    }
    int sumNumbers(TreeNode* root) {
      return DFS(root,0);
    }
};