// a simple program to test
// squares its input value

#include <iostream>

using namespace std;

int main( )
{
   double x;

   cin >> x;
   if (x < 0) {
      cout << x << endl;
   } else if (x == 0) {
      cout << "42" << endl;
   } else {
      cout << x * x << endl;
   }
   return 0;
}