var f:text;
    p,r,fac,facc:int64;
begin
assign(f ,'fact.in');
reset(f);
read(f,p);
close(f);
r:=1;
fac:=5;
while r<p do
  begin
   r:=r+fac;
   fac:=fac*5;
  end;
assign(f ,'fact.out');
rewrite(f);
if r=p then
  write(f,fac)
   else
   begin
      facc:=fac;
      repeat
        if facc mod 5 =0 then
        begin
        facc:=facc div 5;
        dec(r,1);
        end
        else
        begin
        fac:=fac-5;
        facc:=fac;
        end;
      until  r<=p;
if r=p then
     write(f,fac)
      else
     write(f,'-1');
   end;
     close(f);
end.