for (int c1 = 0; c1 <= min(1023, M + 1024); c1 += 1) {
  S1(c1);
  S3(c1);
}
for (int c1 = max(0, M + 1025); c1 <= 1023; c1 += 1) {
  S2(c1);
  S3(c1);
}
for (int c0 = 0; c0 <= min(1023, M + 1024); c0 += 1) {
  S4(c0);
  S6(c0);
}
for (int c0 = max(0, M + 1025); c0 <= 1023; c0 += 1) {
  S5(c0);
  S6(c0);
}