Description

题目描述

There is a rectangular room, covered with square tiles. Each tile is colored either red or black. A man is standing on a black tile. From a tile, he can move to one of four adjacent tiles. But he can‘t move on red tiles, he can move only on black tiles.  Write a program to count the number of black tiles which he can reach by repeating the moves described above. 

有个铺满方形瓷砖的矩形房间，每块瓷砖的颜色非红即黑。某人在一块砖上，他可以移动到相邻的四块砖上。但他只能走黑砖，不能走红砖。

敲个程序统计一下这样可以走到几块红砖上。

Input

输入

The input consists of multiple data sets. A data set starts with a line containing two positive integers W and H; W and H are the numbers of tiles in the x- and y- directions, respectively. W and H are not more than 20.  There are H more lines in the data set, each of which includes W characters. Each character represents the color of a tile as follows.  ‘.‘ - a black tile  ‘#‘ - a red tile  ‘@‘ - a man on a black tile(appears exactly once in a data set)  The end of the input is indicated by a line consisting of two zeros. 

多组测试用例。每组数组开头有两个正整数W和H；W与H分别表示 x- 与 y- 方向上瓷砖的数量。W和W均不超过20。

还有H行数据，每行包含W个字符。每个字符表示各色瓷砖如下。

‘.’- 一块黑砖

‘#’- 一块红砖

‘@’- 一个黑砖上的人（一组数据一个人）

输入以一行两个零为结束。

Output

输出

For each data set, your program should output a line which contains the number of tiles he can reach from the initial tile (including itself).

对于每组测试用例，输出他从起始砖出发所能抵达的瓷砖数量（包括起始砖）。

Sample Input - 输入样例

Sample Output - 输出样例

6 9
....#.
.....#
......
......
......
......
......
#@...#
.#..#.
11 9
.#.........
.#.#######.
.#.#.....#.
.#.#.###.#.
.#.#..@#.#.
.#.#####.#.
.#.......#.
.#########.
...........
11 6
..#..#..#..
..#..#..#..
..#..#..###
..#..#..#@.
..#..#..#..
..#..#..#..
7 7
..#.#..
..#.#..
###.###
...@...
###.###
..#.#..
..#.#..
0 0

45
59
6
13