#include <bits/stdc++.h>
#define endl '\n'
using namespace std;

int n;

int main(){
	cin >> n;
	
	int cnt = 0;
	int curr = 1;
	
	for(int i = 2; i <= n; i++){
		// 第i格有多少米
		curr = curr * 2;
		cnt += curr;
	}
	
	cout << cnt;
	return 0;
}