{

  S3(1, 1);

  for (int c0 = 2; c0 <= M; c0 += 1) {

    S1(c0, 1);

    for (int c1 = 2; c1 < c0; c1 += 1)

      S2(c0, c1);

    S4(c0, c0);

  }

}