Вот, прошу:)
uses
System.Collections.Generic;
var
s: string;
l: List := new List();
begin
readln(s);
s := s.ToLower();
foreach str: string in s.Split(' ') do
foreach ch: char in str do
if (ch in ['а', 'е', 'ё', 'и', 'о', 'у', 'э', 'ю', 'я']) and (l.IndexOf(ch) = -1) then
l.Add(ch);
foreach i: char in l do
write(i, ' ');
end.