#include<stdio.h>

int cnk3(int n, int k) 
{
    const int maxn = n;
    int C[maxn+1][maxn+1];
    for (int i=0; i<=maxn; ++i) 
    {
        C[i][0] = C[i][i] = 1;
        for (int j=1; j<i; ++j)
            C[i][j] = C[i-1][j-1] + C[i-1][j];
    }
    return C[n][k];
}

int main(void) 
{
    int n, k;
    scanf("%d%d", &n,&k); 
    //Input: 3 2  output: 3  
    //Input: 30 10
    //output: 30045015

    printf("%d",cnk3(n,k));
    return 0;
}
