#include<fstream.h>
unsigned long i,pp,c;
int main()
{ifstream f("fact.in");
 ofstream g("fact.out");
 f>>pp;
 f.close();
 if(pp==0) {g<<1<<'\n';g.close();return 0;}
 i=5;
 pp--;
 while(pp)
  {i+=5;
   c=i/5;
   pp--;
   while(c%5==0)
    {pp--;
     c=c/5;
    }
  }
 if(pp==0){g<<i<<'\n';g.close();return 0;}
   else {g<<(-1)<<'\n';g.close();return 0;}
}