#include <iostream>
#include <fstream>
using namespace std;

int main()
{    long int p,c1,contor;
    cin>>p;
    contor=0;
    if(p%6==5) cout<<"-1";
    else
    {c1=p/6;
    p=p-c1;
    if(p==0) cout<<"1";
   else
  {

   while(c1>=5)
   {
       c1=c1/5;
       contor++;
       p=p-c1+contor-1;
   }
    cout<<5*p;}
    }

    return 0;
}