for (int c0 = 1; c0 <= 9; c0 += 1) {
if (c0 >= 6) {
for (int c1 = 1; c1 <= 9; c1 += 1)
s0(c0, c1);
} else if (c0 <= 4) {
for (int c1 = 1; c1 <= 9; c1 += 1)
s0(c0, c1);
} else {
for (int c1 = 1; c1 <= 9; c1 += 1) {
s0(5, c1);
s1(5, c1);
}
}
}