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