#include<fstream.h>      
long long n,p,aux,x=0,i=0;      
int main ()      
{      
ifstream f("fact.in");      
ofstream g("fact.out");      
f>>p;      
if (p==0) g<<1;      
 else {      
while (x<p)      
    {
     aux=i;
     i+=25;x+=6;
     if (x>p)
	 {
	  i=aux;
	   while (x<p)

	    {i+=5;x++;}
          break;}      
    }      
if (x==p) g<<i;      
    else g<<-1;      
       }      
f.close();      
g.close();      
return 0;      
}