#include <iostream>
using namespace std;
int main(){
    int n;
    cin>>n;
        try{
            if(n<=0){
                throw 0;
            }
            if(n>12){
                throw 1;
            }
            long long fact = 1;
            for(int i=1; i<=n; i++){
                fact *= i;
            }
            cout<<fact;
        }
        catch(int x){
         if(x==0)
         cout<<"Invalid "
return 0;
}