After finishing one task at work, Bob is getting bored. So he decides to count some patterns in the -pixel-high by -pixel-wide computer screen his employer gave him. Each pixel is either yellow (lit) or black (unlit).

Bob thinks a rectangle of pixels, with both dimensions at least , is **ugly** if its first and last rows are identical and its first and last columns are identical. *(Note: this definition is the same as the one in Problem 5.)* For example, the following rectangles are ugly:

Please help Bob count the number of ugly sub-rectangles in the screen!

#### Constraints

##### Subtask 1 [10%]

##### Subtask 2 [20%]

##### Subtask 3 [70%]

No additional constraints.

#### Input Specification

The first line contains two space-separated integers, and .

The next lines each contain a string of characters—`Y`

for yellow and `B`

for black—representing the colours of the pixels on the screen.

#### Output Specification

Output one integer, the number of ugly sub-rectangles.

#### Sample Input

```
3 3
BYB
YYY
BYB
```

#### Sample Output

`1`

## Comments