#include <iostream>
using namespace std;

// Returns the sum of numbers from 1 to x
int sum(int number);

int main() {
    int number;
    cout << "Enter the largest number: ";
    cin >> number;
    cout << sum(number) << endl;
}

int sum(int number) {
    if (number == 1) {
        return 1;
    } else {
        int result = sum(number - 1);
        return number + result;
    }
}