K. Known Issue
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

Oel's dishonesty is a known issue.

This time he is running for mayor, and, to assure his victory, he's going to hang a poster containing fake news on the greatest wall in the city.

Fortunately, our hero Leo placed some nails on the wall to stop Oel from hanging a big poster. Help Leo find out the area of the biggest poster Oel can hang on the wall.

A poster is a rectangular item that can only be hung on a contiguous nail-free area of the wall, with vertical/horizontal orientation.

Input

The first line of input contains two integers $$$n,m$$$ ($$$1 \lt n,m \lt 250$$$), the dimensions of the wall. The next $$$n$$$ lines contain $$$m$$$ characters each. The coordinate $$$(i,j)$$$ on the wall contains a nail if the $$$j$$$-th character of the $$$i$$$-th line is a '.', and it doesn't if the character is a '#'.

Output

Print a single integer, the area of the biggest poster that can be hung under the given restrictions.

Examples
Input
5 5
#####
#####
#####
#####
#####
Output
25
Input
5 5
##..#
####.
#####
#####
.####
Output
12
Note

The green rectangle shows a possible solution for sample $$$2$$$.