// RawSum.cpp
// tom bailey   22 jan 07

// Request n.
// Print the sum of the integers from 1 to n.

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

int main() {
	cout << "Enter last integer in sum: ";
	int n( 0 );
	cin >> n;
	int sum( 0 );
	for( int i=1; i<=n; ++i ) {
		sum += i;
	}
	cout << sum << endl;

	return 0;
}