#include<bits/stdc++.h>
using namespace std;
int getSum(int n)
{
    if(n==0) 
        return n;
    return n + getSum(n-1);
}
int main()
{
    int n;
    cout << "Enter a number : "; 
    cin >> n;
    int sum = getSum(n);
    cout << sum;
    return 0;
}