program watera(input,output);

var
  i,j,n,nn,k,ans:longint;
  k2:array[0..30]of longint;
  bo:array[0..30]of byte;

begin
  assign(input,'watera.in');
  reset(input);
  assign(output,'watera.out');
  rewrite(output);

  readln(n,k);
  k2[0]:=1;
  for i:=1 to 30 do
    k2[i]:=k2[i-1] shl 1;

  i:=30;
  while i>=0 do
    if k2[i]>n then
      dec(i)
    else
    begin
      inc(nn);
      n:=n-k2[i];
      bo[i]:=1;
      dec(i);
    end;

  for i:=0 to 30 do
  begin
    if nn<=k then
      break;

    if bo[i]=1 then
    begin
      ans:=ans+k2[i];
      inc(bo[i+1]);
    end
    else if bo[i]=2 then
    begin
      inc(bo[i+1]);
      dec(nn);
    end;
  end;

  writeln(ans);

  close(input);
  close(output);
end.