#include <iostream>
#include <fstream>
using namespace std;
ifstream f("fact.in");
ofstream g("fact.out");
int n,p,k,f2,f5;
int main()
{
   f>>p;
   if(p==0)
   {
       g<<1;
       return 0;
   }
    for(n=2;;n++)
       {
           k=n;
           while(k%2==0)
            k/=2,f2++;
            while(k%5==0)
                k/=5,f5++;
            if(min(f2,f5)==p)
            {
                g<<n;
                return 0;
            }
            if(min(f2,f5)>p)
            {
                g<<-1;
                return 0;
            }
       }
   return 0;
}