{

  for (int c0 = 1; c0 <= min(M, N); c0 += 1) {

    S1(c0);

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

      S2(c0, c1);

  }

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

    S1(c0);

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

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

      S2(c0, c1);

}