#include <stdio.h>

long m,n,p;
FILE *f,*g;
int main()
{f=fopen("fact.in","r");
g=fopen ("fact.out","w");
fscanf (f,"%ld",&p);
n=0;


if (p==0) fprintf (g,"1");
else
{while (p!=0) {n=n+5;

              if (n%25==0) { m=n;
                  m=m/25;
                             p=p-2;
                             while (m%5==0) {p=p-1;
                                             m=m/5;}}
                                             else p=p-1;

                    }

if (p<0) fprintf (g,"-1");
          else fprintf (g,"%ld",n);}
          fclose(f);
          fclose(g);


    return 0;
}