(n0 + n1) % m = 0, n0 % m + n1 < m, n0 ≤ n0 + n1 ⊦ n0 % m = 0
n0 % m + n1 < m, n0 ≤ (n0 + n1) / m * m ⊦ n0 % m = 0, (n0 + n1) % m = 0