Place digits from 1-9 in every cell, so that no digit repeats in a row, column, or 3x3 region. The dashed lines indicate the boundaries of regions, and cells on the lines are simultaneously part of the regions on both sides of the line. Adjacent digits on a green line differ by at least 5. On a blue line, the sum of digits on the line is the same in each region the line passes through. Cells on a region boundary count toward both regions' sums.