#include <iostream> 
using namespace std; 
 
int main() 
{ 
    int i,p,n; 
    cin>>n; 
    i=1; 
    p=1; 
    while (i<=n) 
    {p=p*i; 
    i=i+1; 
    } 
    cout<<p; 
    return 0; 
}