#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
  ifstream f("nunta.in");
  ofstream g("nunta.out");
int main()
{ int n;
    f>>n;
    if(n==1)g<<1;
    else if(n%2==0)cout<<pow(2,n-1)-1;
    else g<<pow(2,n-1);
        return 0;
}