Find the largest island on the map and print its size.
Take the following map for example:
~~~~~~#~
~###~~~~
~##~~~~#
~~~###~~
~~~###~~
~~~~~~~~
~~~~##~~
The character '#' means land and the character '~' means water.
The size of the largest island on the map is the 6.
Note that two '#'s are considered connected only if they are horizontal or vertical neighbors. Diagonal neighbors are not considered connected.
The first line contains two integers m, n, representing the height and width of the map.
The next m lines contain n characters, either '~' or '#' for the mth row of the map.
It is guaranteed that 1 ≤ m, n ≤ 1000
The size of the largest island on the map. Please include a newline character '\n' at the end of the output.