var f:text;
    p,r,fac,facc:longint;
begin
assign(f ,'fact.in');
reset(f);
read(f,p);
close(f);
r:=0;
fac:=1;
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
   while r>p do
   Begin
    facc:=fac;
     while facc mod 5=0 do
     begin
      facc:=facc div 5;
      r:=r-1;
     end;
    fac:=fac-5;
   End;
    if r=p then
     write(f,fac)
      else
     write(f,'-1');
     end;
     close(f);
end.