#include<bits/stdc++.h>
using namespace std;
long long int fac[30];
void fact()
{
    fac[0]=1;
    for(int i=1;i<=20;i++)
        fac[i]=fac[i-1]*i;
}
int main()
{
   fact();
   long long int n,i,j;
   while(cin>>n)
   {
       if(n<7 && n>0 )
        cout<<"Underflow!"<<endl;
       else if(n>13)
        cout<<"Overflow!"<<endl;
       else
        cout<<fac[n]<<endl;
   }
   return 0;
}