var d5,m,n:longint;
    p:1..100000000;
    f,g:text;
begin
assign(f,'fact.in');
assign(g,'fact.out');
reset(f);
read(f,p);
while d5<p do begin
      n:=n+5;
      m:=n;
      while m mod 5=0 do begin
            m:=m div 5;
            d5:=d5+1;
      end;
end;
rewrite(g);
if p=0 then write(g,'1')
       else if d5=p then write(g,n)
                    else write(g,'-1');

close(f);
close(g);
end.