3049. 다각형의 대각선

c
#include <bits/stdc++.h>

using namespace std;

int main(){
    cin.tie(NULL);
    cout.tie(NULL);
    ios_base::sync_with_stdio(false);

    int N;
    cin >> N;
    
    cout << N * (N - 1) * (N - 2) * (N - 3) / 24 << "\n";

    return 0;
}