//Haha TTpro
//BCFACT
//http://www.spoj.com/PTIT/problems/BCFACT/


#include <iostream>

using namespace std;
long long int giaithua(int a);
int main()
{
    int a;
    long long int s;
    while (true)
    {
    cin >>a;
    s= giaithua(a);
    cout<<s<<endl;
    }
}


long long int giaithua(int a)
{
  long long int s=1;
  int i;
  for (i=1;i<=a;i++)
  {
      s=s*i;
  }
return s;
}