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from math import comb

a = list(map(int, input().strip().split()))

n = a[0]
m = a[1]

board = []
targetBoard = []

for i in range(0, n):
    stringInput = input()
    board.append(stringInput)

empty = input()

for i in range(0, n):
    stringInput = input()
    targetBoard.append(stringInput)

boardArray = [[0 for x in range(m)] for y in range(n)]
targetBoardArray = [[0 for x in range(m)] for y in range(n)]

numberOfPawns = 0

pairityStart = 0
pairityEnd = 0

i = 0
for line in board:
    j = 0
    for character in line:
        if character == ".":
            boardArray[i][j] = 0
        elif character == "O":
            boardArray[i][j] = 1
            pairityStart += i + j
            numberOfPawns += 1

        j += 1
    i += 1

i = 0
for line in targetBoard:
    j = 0
    for character in line:
        if character == ".":
            targetBoardArray[i][j] = 0
        elif character == "O":
            targetBoardArray[i][j] = 1
            pairityEnd += i + j

        j += 1
    i += 1

pairityStart = pairityStart % 2
pairityEnd = pairityEnd % 2

# print(pairityStart)
# print(pairityEnd)

if pairityStart != pairityEnd:
    print(0)
    exit(0)

if numberOfPawns == 1:
    totalWays = 0

    for i in range(0, n):
        for j in range(0, m):

            if (i + j) % 2 == pairityStart:
                if i - 1 >= 0:
                    totalWays += 1

                if i + 1 < n:
                    totalWays += 1

                if j - 1 >= 0:
                    totalWays += 1

                if j + 1 < m:
                    totalWays += 1

            # print(totalWays)

    for i in range(0, n):
        for j in range(0, m):
            ways = 0
            if (i + j) % 2 == pairityStart:
                if i - 1 >= 0:
                    ways += 1

                if i + 1 < n:
                    ways += 1

                if j - 1 >= 0:
                    ways += 1

                if j + 1 < m:
                    ways += 1

            if targetBoardArray[i][j] == 1:
                print(ways / totalWays)

if numberOfPawns > 1:
    combinations = comb(n * m, numberOfPawns)
    boardPairityMap = [[0 for x in range(m)] for y in range(n)]
    divisible = 0
    nonDivisible = 0

    for i in range(0, n):
        for j in range(0, m):
            if (i + j) % 2 == 0:
                boardPairityMap[i][j] = 0
                divisible += 1
            else:
                boardPairityMap[i][j] = 1
                nonDivisible += 1

    # print(divisible)
    # print(nonDivisible)

    # print(numberOfPawns)

    sumOfDivisibleSubsums = 0

    pairityCases = []

    for a in range(0, numberOfPawns + 1):
        pairityCases.append([a, numberOfPawns - a])

    # print(pairityCases)

    for case in pairityCases:
        # print(case)
        # print(comb(nonDivisible, case[0]) * comb(divisible, case[1]))
        if case[0] % 2 == 0:
            sumOfDivisibleSubsums += comb(nonDivisible, case[0]) * comb(divisible, case[1])

    # print(sumOfDivisibleSubsums)

    # print(combinations)

    if pairityStart == 0:
        print(1/sumOfDivisibleSubsums)
    else:
        print(1/(combinations-sumOfDivisibleSubsums))