public class  {
    class TreeNode {
        int val = 0;
        TreeNode left = null;
        TreeNode right = null;
        public TreeNode(int val) {
            this.val = val;
        }
    }
    
    public int handle(TreeNode root){
        if (root == null)
            return 0;
        int left = handle(root.left);
        int right = handle(root.right);
        
        return (left > right)?left+1:right+1;
    }
}