문제
풀이
#include <iostream>
using namespace std;
long long fac(int n) {
long long ret = 1;
for (int i=2; i<=n; i++) ret *= i;
return ret;
}
void solve(void) {
int n, a, b, c; cin >> n >> a >> b >> c;
cout << fac(n) / (fac(a) * fac(b) * fac(c));
}
int main(void) {
ios::sync_with_stdio(false);
cin.tie(nullptr);
solve();
return 0;
}