How many are perpendicular?
How many are horivontal?
how many have a gradient of 1 ?
how many have a gradient of -1 ?
how many have a gradient of 1 ?
how many have a gradient of 1 /2?
how many have a gradient of -1/2 ?
how many have a gradient of 2 ?
how many have a gradient of -2 ?
Add them together