PROGRAM Sieve (Input,Output);

CONST
  Max = 1000;

VAR
  A : Array[1..Max] Of 0..1;
  I, Skip : Integer;

BEGIN
  FOR I:= 1 to Max DO
    A[I] := 0;

  FOR Skip := 2 to Max DO
    FOR I := 1 To Max Div Skip DO
      IF A[I*Skip] = 0 THEN
        A[I*Skip] := 1
      ELSE
        A[I*Skip] := 0;

  FOR I := 1 TO Max DO
   Write(A[I]:1);
END.