Problem Statement

We have a grid with $H$ horizontal rows and $W$ vertical columns of squares, where each square is tidy or untidy.

You will now place a mattress on this grid.

The mattress can be placed on two horizontally or vertically adjacent tidy squares in the grid.

Given are integers $H$, $W$, and $H$ strings $S_i$ of length $W$ each. If the $j$-th character of $S_i$ is ., the square at the $i$-th row from the top and the $j$-th column from the left is tidy; if the $j$-th character of $S_i$ is #, the square at the $i$-th row from the top and the $j$-th column from the left is untidy.

Find the number of ways to choose the position for the mattress.

Constraints

• $2 \leq H \leq 100$
• $2 \leq W \leq 100$
• $S_i$ is a string of length $W$ consisting of . and #.

Sample Input 1Copy

2 3
..#
#..

Sample Output 1Copy

3

We have the following three choices:

• the $1$-st and $2$-nd squares from the left in the $1$-st row from the top;
• the $2$-nd and $3$-rd squares from the left in the $2$-nd row from the top; and
• the $1$-st and $2$-nd squares from the top in the $2$-nd column the left.

Sample Input 2Copy

2 2
.#
#.

Sample Output 2Copy

0