q198457157

program q198457157;

var s, t, g: string;
    i, j: integer;

begin
  readln(s);

  t := '';
  for i := 1 to Length(s) do
  begin
    if (s[i] = ' ') then
    begin
      g := '';
      for j := i + 1 to Length(s) do
      begin
        if (s[j] = ' ') then
        begin
          if (t = g) then
          begin
            Writeln(t);
            break;
          end;
          g:='';
        end else begin
          g := g + s[j];
        end;
      end;
      t := '';
    end else begin
      t := t + s[i];
    end;
  end;
end.