View Code of Problem 73

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int n = scanner.nextInt();
		int sum =1 ;
		for(int i=1; i<n; i++ ) {
			sum = (sum +1)*2;
		}
		
		System.out.println(sum);
	}
}