#include <iostream>
using namespace std;
 int main()
 {
     long long n, results=1;
      int i, j;
      
      
     
                  cin>>n;
                  
                  for(i=n; i>=1; i--)
                  {
                           results=results*i;
                           }
                           cout<<endl<<results;
    
     return 0;
}
        