//The following three lines are needed to get a number from the keyboard.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Sum3 {
	public static void main(String[] args) {
		System.out.print("What number do you want to sum up to? ");
		int n = getInt();
		int sum = 0;

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

		System.out.println("The sum of the numbers from 1 to " + n
			+ " is " + sum + ".");
	}

	//The following 16 lines are needed to get a number from the keyboard.
	private static BufferedReader reader =
		new BufferedReader(new InputStreamReader(System.in));
	private static int getInt() {
		try {
			return Integer.parseInt(reader.readLine());
		}
		catch (IOException e) {
			System.err.println("Couldn't receive input: "
				+ e.getMessage());
		}
		catch (NumberFormatException e) {
			System.err.println(e.getMessage()
				+ ", the characters were not a number.");
		}
		return 0;
	}
}