#include<bits/stdc++.h>
using namespace std;
int fact(int n){
	int factorial=1;
	for(int i=1;i<=n;i++)
	    factorial*=i;
    return factorial;
}
int main(){
	int n,m;
	cin>>n>>m;
	cout<<fact(n)/(fact(n-m)*fact(m));\
	return 0;
}```