#ifndef ONLINE_JUDGE
#define _GLIBCXX_DEBUG
#endif
#include <bits/stdc++.h>
#include <cassert>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using mint = modint998244353;
//using mint = modint1000000007;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repu(i, s, t) for (int i = (int)(s); i < (int)(t); i++)
#define repd(i, s, t) for (int i = (int)(s)-1; i >= (int)(t); i--)
#define all(v) v.begin(), v.end()
void _u() { cerr << endl; } template <class H, class... T> void _u(H&& h, T&&... t) { cerr << h << ", "; _u(move(t)...); }
#define U(...) { cerr << #__VA_ARGS__ << ": "; _u(__VA_ARGS__); }
template<typename T> bool chmax(T &a, const T b) { if(a >= b) return false; a = b; return true; }
template<typename T> bool chmin(T &a, const T b) { if(a <= b) return false; a = b; return true; }
template<typename T> istream& operator>>(istream &in, vector<T> &a) { for(T &x: a) in >> x; return in; }
template<typename T> ostream& operator<<(ostream &out, const vector<T> &a) { for(const T &x: a) out << x << ' '; return out; }
const int di[] = {1, 0, -1, 0, 1, 1, -1, -1, 0};
const int dj[] = {0, 1, 0, -1, -1, 1, 1, -1, 0};


struct modinv {
    int n; vector<mint> d;
    modinv(): n(2), d({0,1}) {}
    mint operator()(int i) {
        while (n <= i) d.push_back(-d[mint::mod()%n]*(mint::mod()/n)), ++n;
        return d[i];
    }
    mint operator[](int i) const { return d[i];}
} invs;
struct modfact {
int n; vector<mint> d;
modfact(): n(2), d({1,1}) {}
mint operator()(int i) {
    while (n <= i) d.push_back(d.back()*n), ++n;
    return d[i];
}
mint operator[](int i) const { return d[i];}
} facts;
struct modfactinv {
    int n; vector<mint> d;
    modfactinv(): n(2), d({1,1}) {}
    mint operator()(int i) {
        while (n <= i) d.push_back(d.back()*invs(n)), ++n;
        return d[i];
    }
    mint operator[](int i) const { return d[i];}
} ifacts;
mint comb(int n, int k) {
    if (n < k || k < 0) return 0;
    return facts(n)*ifacts(k)*ifacts(n-k);
}

int main() {
    int n, m;
    cin >> n >> m;
    vector<string> s(n);
    cin >> s;

    vector<int> b(3), q(3);
    rep(i, n) rep(j, m) {
        if(s[i][j] == 'B') b[(i+j)%3]++;
        if(s[i][j] == '?') q[(i+j)%3]++;
    }

    vector<mint> odd(3), even(3);
    rep(i, 3) {
        rep(j, q[i]+1) {
            if((b[i] + j)&1) odd[i] += comb(q[i], j);
            else even[i] += comb(q[i], j);
        }
    }
    mint ans = odd[0] * odd[1] * odd[2] + even[0] * even[1] * even[2];
    cout << ans.val() << endl;
    return 0;
}