#include <iostream>
#include <chrono>
using std::cin;
using std::cout;
using std::endl;

void question1(int n)
{
    float sum = 0;

    for (int i = 0; i <= n; i++)
        sum = sum - (i * i);
}

void question2(int n)
{
    float sum = 0;

    for (int i = 1; i <= (3 * n); i++)
    {
        for (int j = 1; j <= 3; j++)
            sum = sum - j*j;
    }
}

void question3(int n)
{
    float sum = 0;

    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= i; j++)
            sum = sum - j*j;
    }
}

void main()
{
    while (true)
    {
        //Prompt
        cout << "Number of Iterations: ";
        int n;
        cin >> n;

        if (n < 0)
            break;

        //Current time
        auto startTime = std::chrono::high_resolution_clock::now();

        //Call the function
        //question1(n);
        //question2(n);
        question3(n);

        //End time
        auto endTime = std::chrono::high_resolution_clock::now();

        //Time difference
        std::chrono::duration<double> executionTime = std::chrono::duration_cast<std::chrono::duration<double>>(endTime - startTime);
        std::cout << "Program Time = " << executionTime.count() << "s" << std::endl;
    }
}