j0 + i0 = i2 * j + j1, 0 ≤ j1, j1 < j, 0 ≤ j0 + i0, 0 ≤ i0, 0 ≤ j0, j0 < j, 0 ≤ i1, 0 < j ⊦ j1 = ((i1 * j + j0) + i0) % j