[stil]

Код:

var s:string;
    i,j,l:integer;
    b:boolean;
begin
write('s=');readln(s);
l:=Length(s);
for i:=1 to l do begin
  b:=true;
  for j:=1 to l do
    if (s[i]=s[j]) and (i<>j) then b:=false;
    if b then write(s[i]);
end;
readln;