for (int c0 = 0; c0 <= 9; c0 += 2)

  for (int c1 = 0; c1 <= min(4, c0 + 3); c1 += 2)

    for (int c2 = max(1, c0); c2 <= min(c0 + 1, c0 - c1 + 4); c2 += 1)

      for (int c3 = max(1, -c0 + c1 + c2); c3 <= min(4, -c0 + c1 + c2 + 1); c3 += 1)

        S1(c0 / 2, (-c0 + c1) / 2, -c0 + c2, -c1 + c3);