while 1:

	H,W = list(map(int,input().split()))

	if H == 0: break

	M = [input() for i in range(H)]

	A = [[0]*W for i in range(H)]

	B = [[0]*W for i in range(H)]

	ans = 0

	for h in range(H):

		L = 0

		for w in range(W):

			if M[h][w] == ".":

				L += 1

			else:

				L = 0

			A[h][w] = L

			B[h][w] = (B[h-1][w] if h > 0 else 0) + 1 if L > 0 else 0

			if L*B[h][w] > ans:

				a = min([A[h-i][w] for i in range(ans/L+1)])

				for hi in range(B[h][w]):

					a = min(a,A[h-hi][w])

					if a*B[h][w] <= ans:

						break

					ans = max(ans,a*(hi+1))

	print(ans)
while 1:

	H,W = list(map(int,input().split()))

	if H == 0: break

	M = [input() for i in range(H)]

	A = [[0]*W for i in range(H)]

	B = [[0]*W for i in range(H)]

	ans = 0

	for h in range(H):

		L = 0

		for w in range(W):

			if M[h][w] == ".":

				L += 1

			else:

				L = 0

			A[h][w] = L

			B[h][w] = (B[h-1][w] if h > 0 else 0) + 1 if L > 0 else 0

			if L*B[h][w] > ans:

				a = L

				for hi in range(B[h][w]):

					a = min(a,A[h-hi][w])

					if a*B[h][w] <= ans:

						break

					ans = max(ans,a*(hi+1))

	print(ans)
while 1:
    H, W = list(map(int, input().split()))
    if H == 0:
        break
    M = [input() for i in range(H)]
    A = [[0] * W for i in range(H)]
    B = [[0] * W for i in range(H)]
    ans = 0
    for h in range(H):
        L = 0
        for w in range(W):
            if M[h][w] == ".":
                L += 1
            else:
                L = 0
            A[h][w] = L
            B[h][w] = (B[h - 1][w] if h > 0 else 0) + 1 if L > 0 else 0
            if L * B[h][w] > ans:
                a = min([A[h - i][w] for i in range(ans / L + 1)])
                for hi in range(B[h][w]):
                    a = min(a, A[h - hi][w])
                    if a * B[h][w] <= ans:
                        break
                    ans = max(ans, a * (hi + 1))
    print(ans)

while 1:
    H, W = list(map(int, input().split()))
    if H == 0:
        break
    M = [input() for i in range(H)]
    A = [[0] * W for i in range(H)]
    B = [[0] * W for i in range(H)]
    ans = 0
    for h in range(H):
        L = 0
        for w in range(W):
            if M[h][w] == ".":
                L += 1
            else:
                L = 0
            A[h][w] = L
            B[h][w] = (B[h - 1][w] if h > 0 else 0) + 1 if L > 0 else 0
            if L * B[h][w] > ans:
                a = L
                for hi in range(B[h][w]):
                    a = min(a, A[h - hi][w])
                    if a * B[h][w] <= ans:
                        break
                    ans = max(ans, a * (hi + 1))
    print(ans)

-                a = min([A[h - i][w] for i in range(ans / L + 1)]) +                a = L