#include<iostream>
using namespace std;

int getVal();
void doStuff (int);
int y = 2;

int main() {
   int x;

loop:
   x = getVal();

   doStuff (x);
}

int getVal() {
   int val;
   cin >> val;
   if (val == 0)
      goto place;

   return val;
}

void doStuff (int n) {
   n = n * y;
   y = y * 2;
   cout << n << endl;
   goto loop;

place:
   exit (-1);
}