import sys, time, random
from collections import deque, Counter, defaultdict
import logging
from logging import debug, error, info, warning
logging.basicConfig(level=logging.DEBUG)
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 61 - 1
mod = 998244353
class Combinatorics():
    def __init__(self, mod, maxi):
        self.mod = mod
        self.maxi = maxi
        self.facs = [1] * (maxi + 1)
        self.factinvs = [1] * (maxi + 1)
        self.invs = [1] * (maxi + 1)
        for i in range(2, self.maxi + 1):
            self.facs[i] = ((self.facs[i-1] * i) % self.mod)
            self.invs[i] = (-self.invs[self.mod % i] * (self.mod // i)) % self.mod
            self.factinvs[i] = (self.factinvs[i-1] * self.invs[i]) % self.mod
            
    def choose(self, n, k):
        if k < 0 or k > n: return 0
        if k == 0 or k == n: return 1
        k = min(k, n - k)
        return (((self.facs[n] * self.factinvs[k]) % self.mod) * self.factinvs[n-k]) % self.mod
    
    def perm(self, n, k):
        return (self.choose(n, k) * self.facs[k]) % self.mod

    def homop(self, n, k):
        if n == k == 0:
            return 1
        return self.choose(n + k - 1, k)
C = Combinatorics(mod, 10 ** 5)
n, m = mi()
s = [input() for _ in range(n)]
cnt = [0, 0, 0]
qu = [0, 0, 0]
for i in range(n):
    for j in range(m):
        if s[i][j] == 'B':
            cnt[(i + j) % 3] += 1
        elif s[i][j] == '?':
            qu[(i + j) % 3] += 1
    
ans = 0
queven = [0, 0, 0]
quodd = [0, 0, 0]

for i in range(3):
    for j in range(0, qu[i] + 1, 2):
        queven[i] += C.choose(qu[i], j)
        queven[i] %= mod
    for j in range(1, qu[i] + 1, 2):
        quodd[i] += C.choose(qu[i], j)
        quodd[i] %= mod
    
#000
ret = 1
for i in range(3):
    if cnt[i] % 2:
        ret *= queven[i]
        ret %= mod
    else:
        ret *= quodd[i]
        ret %= mod
ans += ret

ret = 1
for i in range(3):
    if cnt[i] % 2 == 0:
        ret *= queven[i]
        ret %= mod
    else:
        ret *= quodd[i]
        ret %= mod
ans += ret

print(ans % mod)