public class LittleGauss {
	public static void main(String[] args) {
		Long input = null;
		input = Long.parseLong(args[0]); 
		
		//long power = 1000000;
		long power = 1;
		long time = System.nanoTime();
		long result = 0;
		long timeItTook = 0;
		try {
			result = recursion(input);
			timeItTook = System.nanoTime() - time;
			System.out.println("recursion yields " + result + " and took " + timeItTook/power + " ns.");
		} catch (StackOverflowError e) {
			System.out.println("recursion led to a stack overflow");
		}

		time = System.nanoTime();
		result = loop(input);
		timeItTook = System.nanoTime() - time;
		System.out.println("loop yields " + result + " and took " + timeItTook/power + " ns.");

		time = System.nanoTime();
		result = gauss(input);
		timeItTook = System.nanoTime() - time;
		System.out.println("gauss yields " + result + " and took " + timeItTook/power + " ns.");
	}

	static long recursion(long n) {
		if (n > 0)
			return n + recursion(n - 1);
		else
			return 0;
	}

	static long loop(long n) {
		long sum = 0;
		for (int i = 1; i <= n; i++)
			sum += i;
		return sum;
	}

	static long gauss(long n) {
		return (n * (n + 1L))/ 2;
	}
}