program Leter;
type let=set of 'a'..'z';
st=string;
var s1:string; h,h1,h2:let; c:'a'..'z';
procedure in_word (s:string; var ss:let);
var i:integer;
begin
ss:=[];
for i:=1 to length(s) do
if s[i] in h then ss:=ss+[s[i]]
end;
begin
h:=['b','c','d','f','g','h','k','l','m','n','p','q','r','s','t','v','w','x','z'];
writeln('Введите строку');
readln(s1);
in_word(s1,h1);
h2:=h-h1;
for c:='a' to 'z' do
if c in h2 then writeln(c)
end.