A B C D E
F G H I
J K L
M N
O
B = 3, H = 1, J = 2.
Numbers 1 to 15 must ALL be used.
Where applicable, a number is equal to the
difference of the 2 adjacent numbers above it.
As example, if K=5 and L=9 (or K=9 and L=5), then N=4.
Ya'll know what to do: fill the grid!