Queen Move

Very easy

Execution time limit is 1 second

Runtime memory usage limit is 128 megabytes

There is a queen on the chessboard of size $m \times n$ . How many squares does the queen attack?

Input

Four positive integers: the size of the chessboard $m$ and $n$ and the queen's coordinates $x$ and $y (1 \leq x \leq m \leq 1 0^{9}, 1 \leq y \leq n \leq 1 0^{9})$ .

Output

Print the number of squares the queen attacks.

Examples

Input #1

Answer #1

Input #2

Answer #2

Submissions 1K

Acceptance rate 44%