Contest Duration: - (local time) (100 minutes) Back to Home
D - Weak Takahashi /

Time Limit: 2 sec / Memory Limit: 1024 MB

### 問題文

H 行、横 W 行の H \times W マスからなるグリッドがあります。上から i 行目、左から j 列目のマスを (i, j) と表します。

### 制約

• 1 \leq H, W \leq 100
• H, W は整数
• C_{i, j} = . または C_{i, j} = # (1 \leq i \leq H, 1 \leq j \leq W)
• C_{1, 1} = .

### 入力

H W
C_{1, 1} \ldots C_{1, W}
\vdots
C_{H, 1} \ldots C_{H, W}


### 入力例 1

3 4
.#..
..#.
..##


### 出力例 1

4


5 マス以上通ることはできないので、4 と出力します。

### 入力例 2

1 1
.


### 出力例 2

1


### 入力例 3

5 5
.....
.....
.....
.....
.....


### 出力例 3

9


Score : 400 points

### Problem Statement

There is a H \times W-square grid with H horizontal rows and W vertical columns. Let (i, j) denote the square at the i-th row from the top and j-th column from the left.
Each square is described by a character C_{i, j}, where C_{i, j} = . means (i, j) is an empty square, and C_{i, j} = # means (i, j) is a wall.

Takahashi is about to start walking in this grid. When he is on (i, j), he can go to (i, j + 1) or (i + 1, j). However, he cannot exit the grid or enter a wall square. He will stop when there is no more square to go to.

When starting on (1, 1), at most how many squares can Takahashi visit before he stops?

### Constraints

• 1 \leq H, W \leq 100
• H and W are integers.
• C_{i, j} = . or C_{i, j} = #. (1 \leq i \leq H, 1 \leq j \leq W)
• C_{1, 1} = .

### Input

Input is given from Standard Input in the following format:

H W
C_{1, 1} \ldots C_{1, W}
\vdots
C_{H, 1} \ldots C_{H, W}


### Sample Input 1

3 4
.#..
..#.
..##


### Sample Output 1

4


For example, by going (1, 1) \rightarrow (2, 1) \rightarrow (2, 2) \rightarrow (3, 2), he can visit 4 squares.

He cannot visit 5 or more squares, so we should print 4.

### Sample Input 2

1 1
.


### Sample Output 2

1


### Sample Input 3

5 5
.....
.....
.....
.....
.....


### Sample Output 3

9