Pbinfo - Expresie

#include <iostream>
#include <fstream>
#include <cmath>

using namespace std;

int n; // catevba de aici le poti ignora
int x, s, i = 0;
int a, b;

int main()
{
    cin >> n;
    unsigned long long int s=0, p=1;
    for (int i=1; i<=n; i++)
    {
        p=1;
        for (int j=1; j<=i; j++)
        {
            p *= j;
        }
        s += p;
    }
    cout << "Rezultatul este " << s;
    return 0;
}