using System;

​

public class Program

{

    public Tree head;

    public int mindepth = int.MaxValue;

    public class Tree

    {

        public int data;

        public Tree left;

        public Tree right;

        public Tree(int d)

        {

            data = d;

            left = right = null;

        }

    }

​

    public void finddepth(Tree node, int height)

    {

        if (node.left == null && node.right == null)

        {

            if (mindepth > height)

            {

                mindepth = height;

            }

        }

        else

        {

            if (node.left != null)

            {

                finddepth(node.left, height + 1);

            }

​

            if (node.right != null)

            {

                finddepth(node.right, height + 1);

            }

        }

    }

​

    public static void Main()

    {

        Program p = new Program();

        p.head = new Tree(1);

        p.head.left = new Tree(2);

        p.head.right = new Tree(3);

        p.head.left.left = new Tree(4);

        p.head.left.right = new Tree(5);

        p.head.right.right = new Tree(6);

        p.finddepth(p.head, 1);

        Console.WriteLine(p.mindepth);

    }

}