#include<iostream.h>
#include<fstream.h>
ifstream f("fact.in");
ofstream g("fact.out");
long long p,nr,x,q=0;
int main()
{f>>p; q=p;
 while(q>0)
  {q--; nr+=5;
   x=nr;
   while(x)
    {if(x%25==0)
     q--; x/=5;
    }   
  }  
 if(q==0) g<<nr;
  else g<<-1;
 return 0;   
}