var f,g:text;
    n:string;
    j,c,i,iesit:longint;

procedure deschidere;
begin
  assign(f,'cifre.in');
  assign(g,'cifre.out');
  reset(f);
  rewrite(g);
end;

procedure a;
begin
  readln(f,n);
  c:=0;
  iesit:=0;
  for i:=0 to 9 do
    begin
      for j:=length(n) downto 1 do
        if n[j]=chr(i+48) then
          begin
            inc(c);
            delete(n,j,1);
            if c=2 then
              begin
                iesit:=1;
                break;
              end;
          end;
      if iesit=1 then
        break;
    end;
  writeln(g,n);
end;

begin
  deschidere;
  a;
  close(f);
  close(g);
end.