#include <stdio.h>
#include <string.h>

int f(int n, int m);
int main()
{
    int m, n;
    while (scanf("%d %d", &n, &m) != EOF)
    {

        int pathcount = f(n, m);
        printf("%d\n", pathcount);
    }

    return 0;
}

int f(int n, int m)
{
    int ret;
    if (n == 0 || m == 0)
        ret = 1;

    else
    {
        ret = f(n, m - 1) + f(n - 1, m);
    }

    return ret;
}