/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public int findBottomLeftValue(TreeNode root) {
        if(root == null) return 0;
        
        int result = 0;
        Queue<TreeNode> queue = new LinkedList<>();
        queue.add(root);
        
        while(!queue.isEmpty())
        {
            int size = queue.size();
            for(int i=0; i<size; i++)
            {
                TreeNode node = queue.poll();
                if(i==0) result = node.val;
                if(node.left != null) queue.add(node.left);
                if(node.right != null) queue.add(node.right);
            }
        }
        return result;
    }
}