Problems

# Anfisa’s Holiday

# Anfisa’s Holiday

The rectangular hangars have sizes `M`

and `N`

(at first for horizontal lines, and then for vertical lines). It was cluttering up by three-cornered tiles. These tiles were numbered as shown on the picture.

Anfisa can move from one tiles to other only through a general side for a one step. What least quantity of steps has to do Anfisa to the piece of cheese which placed on tile with number `B`

if she is being on the tile with number `A`

?

#### Input

In the first line is sizes of the hangars `M`

and `N`

. In the second line is number of tile `A`

in which Anfisa is being and number of the tile `B`

with the piece of cheese. 1 ≤ `M`

, `N`

≤ 30000.

#### Output

A one number is the quantity of steps of `K`

, which Anfisa has to do.

Input example #1

5 4 25 38

Output example #1

5