#include <iostream>
#include <math.h>

using namespace std;

int main()
{

    int n;
    cout << "Wprowadz N:" << endl;
    cin >> n;

    double h = -3, a=-5, sum = a;

    for (int i = 2; i<= n; i++) {
        a += h;
        sum += a;
    }

    cout << "A:" << a<< endl;
    cout << "Sum:" << sum<< endl;

    return 0;
}