Fill in the grid so that every row, every column, and every 3 x 3 box contains the digits 1
A red arrow means that the digits are going up till they hit this number and for a cyan arrow
they go down till they hit this particular number.
135247896 could get a red arrow with a 5 or a cyan arrow with a 1.
932415678 could get a red arrow with a 9 or a cyan arrow with a 2.
The sums of the digits within each sub-region are equal to each other. In sub-regions there can't be the same digit repeated.