trece

#include <iostream>
using namespace std;

int main() {
	int N = 0;
	do {
		cout << "Upisite N :D \n";
		cin >> N;
	}while( N < 0 ||  N > 31);

	if(N == 0) {
		cout << 1;
		return 0;
	}

	int multi = 2;
	int suma = 1;
	for(int i = 0; i < N; ++i) {
		suma *= multi;
	}
	suma -= 1;
	cout << suma;
	return 0;
}