var
  n, i: integer;
  m: int64;
begin
  readln (n);
  m := 1;
  for i := 1 to n do begin
    m := m * i;
    while (m mod 10 = 0) do begin
      m := m div 10;
    end;
    m := m mod 1000;
  end;
  writeln (m mod 10);
  readln;
  readln;
end.