program password;
uses crt;
var tk, mk: string;
begin
 repeat
 clrscr;
  textcolor (white);
  writeln ('Dang nhap de thoat khoi chuong trinh');
   write ('nhap ten tai khoan: ');   readln (tk);
   write ('nhap mat khau: ');     readln (mk);
   if (tk='vnqt343') and (mk='123456789') then
    exit;
   if (tk<>'vnqt343') or (mk<>'123456789') then
   textcolor (lightred);
   writeln ('ten tai khoan hoac mat khau bi sai. vui long dang nhap lai');
   readln;
  until (tk='vnqt343') and (mk='123456789');
 readln;
end.

uses crt;

var tk, mk : string;

begin

clrscr;

write('nhap tai khoan : '); readln(tk);

write('nahp mat khau : '); readln(mk);

while (tk <> 'vnqt343') or (mk <> '123456789') do

begin

write('nhap lai tai khoan : '); readln(tk);

write('nahp lai mat khau : '); readln(mk);

end;

readln

end.