#include <bits/stdc++.h> using namespace std; int main() { int n, sum; sum = 0; cin >> n; int A[n]; int pro = 1; for (int i = 0; i < n; i++) { pro *= (i + 1); A[i] = pro; } for (int i = 0; i < n; i++) { sum += A[i]; } cout << sum; return 0; }