#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 long fact=1;
        for(int i=;i<=n;i++){
            fact*=i;
        }
        cout<<facts;
    }
    return 0;
}