{

  for (int c1 = 1; c1 <= M; c1 += 1)

    S2(c1);

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

    for (int c2 = c0 + 1; c2 <= M; c2 += 1)

      for (int c3 = 1; c3 < c0; c3 += 1)

        S3(c0, c2, c3);

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

      S4(c1, c0);

    for (int c2 = 1; c2 < c0; c2 += 1)

      S1(c0, c2);

  }

}