/*

// Definition for a Node.

class Node {

    public int val;

    public List<Node> children;

    public Node() {}

    public Node(int _val,List<Node> _children) {

        val = _val;

        children = _children;

    }

};

*/

class Solution {

    public int maxDepth(Node root) {

        if(root==null) return 0;

        return dfs(root);

    }

    public int dfs(Node node){

        if(node==null) return 1;

        int maxx = 0;

        for(Node n:node.children){

            maxx = Math.max(maxx,dfs(n));

        }

        return maxx+1;

    }

}