using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(pathsCount(2,4));

    }

    private static int pathsCount(int m, int n) {

        if (m < 1 || n < 1) return 0;

        var factorials = new int[m+n-1];

        factorials[0] = 1;

        for (var i = 1; i <= m+n-2; i++) {

            factorials[i] = factorials[i-1]*i;

        }

        return factorials[m+n-2] / (factorials[m-1] * factorials[n-1]);

    }

}