Fort Moo#10601

Fort Moo

1 second

128 megabytes

Easy

Bessie is planning to build a rectangular fort.

She has already chosen a site: a rectangular piece of land measuring $n$ meters by $m$ meters. Unfortunately, the site contains some swampy areas where construction is not possible. Please help Bessie determine the largest area she can cover with her fort such that it does not overlap any of the swampy areas.

Input

The first line contains two integers $n$ and $m (1 \leq n, m \leq 200)$ m~(1 \le n, m \le 200). The next $n$ lines each contain $m$ characters, describing the site as a grid. A character ' $.$ ' represents a grassy area, while ' $X$ ' represents a swampy area.

Output

Print the maximum area that Bessie can cover with her fort.

Examples

In the example, the placement of the fort is indicated by ' $f$ ':

.ffff.
.fX.fX
Xf.Xf.
.ffff.
..X...

Example 1