Program PascalGuru;
var
s: string;
litera: set of char;
i: integer;
j: char;
begin
write('Vvedite vashe imya: ');
readln(s);
for i := 1 to length(s) do
if s[i] in ['A' .. 'Z'] then
s[i] := chr(ord(s[i]) + 32);
writeln;
for j := 'a' to 'z' do
if pos(j, s) = 0 then
write(j, ', ');
readln;
end.