// Prog: fak-1.cpp
// compute the n!

#include <iostream>

int main () 
{
  std::cout << "Factorial of n =? ";
  int n;
  std::cin >> n;

  // computation
  unsigned int fak = 1;
  for (unsigned int i = 2; i <= n; ++i) fak *= i;

  // output
  std::cout << "Factorial of " << n << " is " << fak << ".\n";

  return 0;
}