Problem Statement

There is a grid with $H$ horizontal rows and $W$ vertical columns. Let $(i,j)$ denote the square at the $i$-th row from the top and the $j$-th column from the left.
Find the number of squares that share a side with Square $(R, C)$.

Here, two squares $(a,b)$ and $(c,d)$ are said to share a side if and only if $|a-c|+|b-d|=1$ (where $|x|$ denotes the absolute value of $x$).

Constraints

• All values in input are integers.
• $1 \\le R \\le H \\le 10$
• $1 \\le C \\le W \\le 10$

---

Input

Input is given from Standard Input in the following format:

$H$ $W$ $R$ $C$

Output

Print the answer as an integer.

---

Sample Input 1

3 4
2 2

Sample Output 1

4

We will describe Sample Inputs/Outputs $1,2$, and $3$ at once below Sample Output $3$.

---

Sample Input 2

3 4
1 3

Sample Output 2

3

---

Sample Input 3

3 4
3 4

Sample Output 3

2

When $H=3$ and $W=4$, the grid looks as follows.

• For Sample Input $1$, there are $4$ squares adjacent to Square $(2,2)$.
• For Sample Input $2$, there are $3$ squares adjacent to Square $(1,3)$.
• For Sample Input $3$, there are $2$ squares adjacent to Square $(3,4)$.

---

Sample Input 4

1 10
1 5

Sample Output 4

2

---

Sample Input 5

8 1
8 1

Sample Output 5

1

---

Sample Input 6

1 1
1 1

Sample Output 6

0