//

//  1458 汉诺塔III.cpp

//  Jobdu

//

//  Created by PengFei_Zheng on 23/04/2017.

//  Copyright © 2017 PengFei_Zheng. All rights reserved.

//

#include <stdio.h>

#include <iostream>

#include <algorithm>

#include <string.h>

#include <cmath>

using namespace std;

int ans = ;

long long hanoi(int n){

    if(n==) return ;

    if(n==) return ;

    return *hanoi(n-)+;

}

int n;

int main(){

    while(scanf("%d",&n)!=EOF){

        printf("%lld\n",hanoi(n));

    }

}

/**************************************************************

    Problem: 1458

    User: zpfbuaa

    Language: C++

    Result: Accepted

    Time:0 ms

    Memory:1520 kb

****************************************************************/