Problems
Queen Move
Queen Move
There is a queen on the chessboard of size m × n. How many squares does the queen attack?
Input data
Four positive integers: the size of the chessboard m and n and the queen's coordinates x and y~(1 \le x \le m \le 10^9, 1 \le y \le n \le 10^9).
Output data
Print the number of squares the queen attacks.
Examples
Input example #1
8 8 4 5
Output example #1
27
Input example #2
1000000000 3 999999999 2
Output example #2
1000000005