program fact;
var f : text;
    p, n, k, x, l : longint;
begin
assign (f, 'fact.in');
reset (f);
read (f, p);
close (f);
assign (f, 'fact.out');
rewrite (f);
x:=1;
k:=0;
if p>0 then
repeat
 if p*5>=x then begin
                x:=x*5;
                inc (k);
               end;
until p*5<=x;
if k<=3 then l:=(p-k+2)*5;
if k>3 then l:=(p-k+1)*5;
if p=0 then write (f, 1)
       else if p=5 then write (f, -1)
                   else if p=1 then write (f, 5)
                               else write (f, l);
close (f);
end.