/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public int maxLevel = 0;
    public TreeNode nodeLeft;
    public int findBottomLeftValue(TreeNode root) {
        if(root == null)
            return 0;
        nodeLeft = root;
        helper(root, 0);
        
        return nodeLeft.val;
            
    }
    
    public void helper(TreeNode root, int depth){
        if(root==null)
            return;
        if(root.left == null && root.right == null && maxLevel<depth){
            maxLevel = depth;
            nodeLeft = root;
            return;
        }
        helper(root.left, depth+1);
        helper(root.right, depth+1);
    }
    
}