**Time limit:**1.00 s**Memory limit:**512 MB

What is the maximum area of a rectangular building that can be placed in the forest so that no trees must be cut down?

**Input**

The first input line contains integers $n$ and $m$: the size of the forest.

After this, the forest is described. Each square is empty (

`.`

) or has trees (`*`

).**Input**

Print the maximum area of a rectangular building.

**Constraints**

- $1 \le n,m \le 1000$

**Example**

Input:

`4 7`

...*.*.

.*.....

.......

......*

Output:

`12`