#include <fstream>

using namespace std;
ifstream f("fact.in");
ofstream g("fact.out");

long long n,p,nr,putere;
int main()
{
    f>>p;
    if (p==0)
    g<<"1";
    else
    {
        while (p>0)
         {
           putere=0;
           nr=1;
          while (putere<=p+1)
           {
              putere=putere*5+1;
              nr*=5;
           }
           n+=nr/5;
           p-=(putere-1)/5;

         }
        if (p==0)
         g<<n;
        else
         g<<"-1";
     }
    f.close();
    g.close();
}