#include<iostream.h>
#include<fstream.h>

ifstream in("fact.in");
ofstream out("fact.out");

int main()
{
int p,ok=0,n,twos=0,fives=0,pp;
in>>p;

for(n=1;ok==0 && n>0;n++)
{
pp=n;
while(pp%5==0 || pp%2==0){
if (pp%2==0) { twos++; pp=pp/2;}
if (pp%5==0) { fives++; pp=pp/5;}
}

if(twos>=p && fives>=p) ok=n;
}

if(ok==0) out<<-1;
else out<<ok;

out.close();
in.close();

return 0;
}