using System;

using System.Diagnostics;

public class Program

{

    public static void Main()

    {

        var stopWatch = new Stopwatch();

        stopWatch.Start();

        var number = paths(100, 100);

        stopWatch.Stop();   

        Console.WriteLine(number);

        Console.WriteLine(stopWatch.Elapsed);

    }

    public static long paths(int n, int m)

    {

        var arr = new long [n+1, m+1];

        return helper(n, m, arr);

    }

    public static long helper(int n, int m, long[,] arr)

    {

        if (n < 1 || m < 1)

        {

            return 0;

        }       

        if (n == 1 && m ==1) 

        {

            return 1;

        }       

        if (arr[n,m] != 0) {

            return arr[n,m];

        }

        arr[n,m] = helper(n - 1, m, arr) + helper(n, m - 1, arr);

        return arr[n,m];

    }

}