C++ :

#include<iostream>
using namespace std;
int main()
{
	int n,sum=1;
	cin>>n;
	for (int i=1; i<n; i++)
		sum=2*(sum+1);
	cout<<sum<<endl;
	return 0;
}

Pascal :

var n,i,s:longint;
begin
  readln(n);
  s:=1;
  for i:=1 to n-1 do
  s:=(s+1)*2;
  writeln(s);
end.