#include<stdio.h>
 
unsigned long nCm(int, int);
int gcd(int, int);
 
int main() {
	int n, m;
	scanf("%d,%d", &n, &m);
	printf("%lu\n", nCm(n, m));
	return 0;
}
 
/*
nCm
= (n /m) * n-1Cm-1 (0< m <n)
= 1 (otherwise)
*/
unsigned long nCm(int n, int m) {
 
	if (!(0 < m && m < n)) {
		return 1;
	}
	int g = gcd(n, m);
	return (n / g) * (nCm(n - 1, m - 1) / (m / g));
}
 
//最大公約数を求める
int gcd(int a, int b) {
	if (b == 0) {
		return a;
	}
	return gcd(b, a % b);
}

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