program ds;
  var
    letter:char;
  begin
    for letter:='a' to 'z' do
    if (ord(letter)-ord('a')mod 2=0 then write(letter：3);
    writeln;
    for letter:='z' to 'a' do
    if (ord(letter)-ord('z')mod 2=0 then write(letter: 3);
    writeln;
  end.

记得加分哦