import io
import sys
from collections import defaultdict, deque, Counter
from itertools import permutations, combinations, accumulate
from heapq import heappush, heappop
from bisect import bisect_right, bisect_left
from math import gcd
import math
from itertools import product

_INPUT = """\
6
6 20
....................
.##################.
.#................#.
.##################.
.##################.
....................
####################
#..................#
#.################.#
#..................#
#..................#
####################
"""

def input():
  return sys.stdin.readline()[:-1]

def solve(test):
  H,W=map(int, input().split())
  S=[input() for _ in range(H)]
  T=[input() for _ in range(H)]
  a,b=0,0
  ans=0
  for i in range(H):
    for j in range(W):
      if S[i][j]==T[i][j]:
        a=1
      if S[i][j]==T[H-1-i][W-1-j]:
        b=1
  r=1
  for i in range(50):
    if i%2==0 and a==0 or i%2==1 and b==0:
      k=1-(1/2)**i
    else:
      k=0
    # print(i+1,k)
    ans+=(i+1)*k*r
    r*=1-k
  print(ans)

def random_input():
  from random import randint,shuffle
  N=randint(1,10)
  M=randint(1,N)
  A=list(range(1,M+1))+[randint(1,M) for _ in range(N-M)]
  shuffle(A)
  return (" ".join(map(str, [N,M]))+"\n"+" ".join(map(str, A))+"\n")*3

def simple_solve():
  return []

def main(test):
  if test==0:
    solve(0)
  elif test==1:
    sys.stdin = io.StringIO(_INPUT)
    case_no=int(input())
    for _ in range(case_no):
      solve(0)
  else:
    for i in range(1000):
      sys.stdin = io.StringIO(random_input())
      x=solve(1)
      y=simple_solve()
      if x!=y:
        print(i,x,y)
        print(*[line for line in sys.stdin],sep='')
        break

#0:提出用、1:与えられたテスト用、2:ストレステスト用
main(0)