#include <iostream>
#include <clocale>

using namespace std;

void main()
{
    setlocale(LC_ALL, "Russian");
    int n, k = 0, sum = 0;
    do
    {
        cout << "Введите число N > 1: ";
        cin >> n;
    } while (n <= 1);

    while (sum <= n)
    {
        k++;
        sum += k;
    }
    cout << "K = " << k << endl;
    cout << "sum = " << sum;

    cin.get(); cin.get();
}