#include <stdio.h>

int coeficiente(int n, int k){
    return (k == 0 || k == n) ? 1 : coeficiente(n-1, k) + coeficiente(n - 1, k - 1);
}

int main() {
    int n, k, coef;
    
    scanf("%d %d", &n, &k);
    coef = coeficiente(n, k);
    
    printf("%d", coef);
    return 0;
}