#include<iostream.h>
#include<stdio.h>
FILE *f,*g;
int main ()
{
f=fopen("fact.in","r");
g=fopen("fact.out","w");
long p,n,x;
fscanf(f,"%ld",&p);
n=0;
int t=1; long nr=0;
if(p==0) fprintf(g,"1");
else
while(t)
{
 n++;
 x=n;
 while(x%5==0)
 {
  nr++;
  x/=5;
 }
 if(nr>p) {t=0;fprintf(g,"-1");}
 if(nr==p) {t=0;fprintf(g,"%ld",n);}
}
return 0;
}