for (int c0 = 1; c0 <= n; c0 += 1) {

  S1(c0);

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

    S2(c0, c1);

  S3(c0);

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

    S4(c0, c1);

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

      S5(c0, c1, c2);

    S6(c0, c1);

  }

}