// editor2
#include<iostream>
using namespace std;
int main(){
    int n;
    cin>>n;
    if(n <=0){
        cout<"Invalid input";
    }
    else if(n >12){
     cout<<"Overflow occurred";
    }
    else{
        long result= 1;
        for(int i=1; i<=n; i++){
            result=result*i;
        }
        cout<<result;
    }
    return 0;
}