Problem Background

oibh headquarters has suddenly been flooded! Your rescue is needed...

Problem Description

oibh has been unexpectedly flooded, but fortunately, oibh headquarters has built walls in some important areas, represented by *. A region surrounded by walls on all four sides cannot be flooded.

There are also many important areas within oibh headquarters, each represented by a 0 in the diagram.

Given the construction map of oibh's walls, determine how many important areas, represented by 0, have not been flooded.

Input Format

The first line contains two positive integers $x, y$.

The next $x$ lines, each containing $y$ integers, consist of * and 0, representing the construction map of oibh headquarters.

Output Format

Output the number of 0s in oibh headquarters that are not flooded.

Sample Input and Output

Sample Input #1

4 5
00000
00*00
0*0*0
00*00

Sample Output #1

1

Sample Input #2

5 5
*****
*0*0*
**0**
*0*0*
*****

Sample Output #2

5

Notes

For $100\%$ of the data, $1 \le x, y \le 500$.

见题面 Input 部分

见题面 Output 部分