#!/bin/python3

import math
import os
import random
import re
import sys
from itertools import combinations

# Complete the 'twoPluses' function below.
# The function is expected to return an INTEGER.
# The function accepts STRING_ARRAY grid as parameter.

def twoPluses(grid):
    h, w = len(grid), len(grid[0])
    pluses = []

    def is_good(r, c):
        return 0 <= r < h and 0 <= c < w and grid[r][c] == 'G'

    # Generate all valid pluses
    for r in range(h):
        for c in range(w):
            if not is_good(r, c):
                continue
            size = 0
            occupied = {(r, c)}
            pluses.append((1, occupied.copy()))  # Add single cell plus
            while True:
                size += 1
                cells = {(r+i, c) for i in range(-size, size+1)} | {(r, c+i) for i in range(-size, size+1)}
                if all(is_good(x, y) for x, y in cells):
                    pluses.append((len(cells), cells.copy()))
                else:
                    break

    # Try all combinations of 2 pluses and find max area product of non-overlapping ones
    max_product = 0
    for (area1, cells1), (area2, cells2) in combinations(pluses, 2):
        if cells1.isdisjoint(cells2):
            max_product = max(max_product, area1 * area2)

    return max_product if max_product else 1  # At least one plus is guaranteed

if __name__ == '__main__':
    fptr = open(os.environ['OUTPUT_PATH'], 'w')

    nm = input().split()
    n = int(nm[0])
    m = int(nm[1])

    grid = []
    for _ in range(n):
        grid_item = input()
        grid.append(grid_item)

    result = twoPluses(grid)

    fptr.write(str(result) + '\n')
    fptr.close()