Tesha was walking through a straight street with exactly n identical houses on both sides. House numbers in the street look like this:

1 |   | 6

3 |   | 4

5 |   | 2

She noticed that even numbered houses increase on the right while odd numbered houses decrease on the left.

Create a function that takes a house number house and length of the street n and returns the house number on the opposite side.

Examples

oppositeHouse(1, 3) ➞ 6

oppositeHouse(2, 3) ➞ 5

oppositeHouse(3, 5) ➞ 8

oppositeHouse(5, 46) ➞ 88

Notes

N/A