public class Homework2 {
	public static void main(String[] args) {
		// TEST OUTPUTS

		/*
		// Problem 1
		System.out.println("For 4: " + recurs(4));
		System.out.println("For 5: " + recurs(5));
		*/
		/*
		// Problem 2
		System.out.println(gcd(14, 21));
		*/
		/*
		// Problem 3
		System.out.println(mystery(-4));
		*/

		// Problem 5
		System.out.print(func(3));

		System.out.println("\n");
		return;
	}
	
	// Problem 1
	public static int recurs (int n) {
		if(n==0) return 1;
		return -1*(n-2);
	}
	// Problem 2
	public static int gcd(int x, int y){
		if(y==0) return x;
		return gcd(y, x%y);
	}
	// Problem 3
	public static int mystery(int number) {
		if(number == 0) return number;
		else return(2*number+mystery(number-1));
	}
	// Problem 4
	public static int power(int n, int x){
			if(n==0)  return 1;
			if(n==1)  return x;
			if(n%2==0)return power(x*x, n/2);
			else return x*power(x, n-1);
		}
	// Problem 5
	public static int func(int n) {
		if(n==0) return 1;
		return func(n-1)+3;
	}

}