var f:text; begin assign(f,'KQ.TXT'); rewrite(f); writeln(f,21); writeln(f,11); close(f); end.
2/
uses crt; var s:string; i:byte; begin clrscr; write('Nhap xau: '); readln(s); for i:=length(s) downto 1 do write(s[i]); writeln; for i:=1 to length(s) do if (s[i]>='A') and (s[i]<='z') then write(s[i]); readln end.
