#include <iostream.h>

const bool debug = true;     /* do I want to print debugging info? */

int product(unsigned int n)
{
  /* debugging: print args */
  if (debug) cout << "n (product): " << n << endl;
  
  int total;
  while (n > 0) {
    /* debugging: print loop vars */
    if (debug) cout << "n,total (loop top): " << n << " " << total << endl;

    n = n-1;
    total = total*n;

    /* debugging: print loop vars (and on last iteration, the result) */
    if (debug) cout << "n,total (loop bottom): " << n << " " << total << endl;
  }

  return total;
}

int main()
{
  unsigned int n;
  cin >> n;
  cout << product(n) << endl; /* print 1*...*n */
}