C_Lucky_Numbers.cpp

#include<bits/stdc++.h>
using namespace std;

#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define nline "\n" 
#define int long long
#define fo(i,n) for(int i = 0;i<n;i++)
#define pb push_back
#define F first
#define S second
typedef long double ld;
typedef vector<signed> vi;
typedef vector<vector<signed>> vvi;
typedef vector<int> vll;
typedef vector<vector<int>> vvll;
const int mod = 1e9+7;
long double pi = acos(-1.0); const double EPS = 1e-9;

int myceil(int a , int b){return (a+b-1)/b;}
int myround(int a , int b){return (2*a+b)/(2*b);}

int binpow(int a , int b){
    if(b == 0){
        return 1;
    } else if( b % 2 == 1){
        return a * binpow(a, b - 1);
    }
    int temp = a * a;
    return binpow(temp,b/2);
}
    
signed main(){
    IOS;

    #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout); 
    #endif

    int n; cin >> n;
    int sum = 0;
    while(n){
        sum += binpow(2,n);
        n--;
    }
    cout << sum;



    
    

}