#include<fstream.h>      
long int 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)      
    {i=i+5;aux=i;      
     while (aux)      
       {if (aux%5==0) {x++;aux=aux/5;}      
        else break;}      
    }      
if (x==p) g<<i;      
    else g<<-1;      
       }      
f.close();      
g.close();      
return 0;      
}