// (⁠◕⁠ᴗ⁠◕⁠✿⁠)
 
// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define srep(i, s, n) for (ll i = s; i < (n); i++)
#define len(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
using namespace std;
template<typename T> using vc = vector<T>;
template<typename T> using vv = vc<vc<T>>;
template<typename T> using vvv = vv<vc<T>>;
using vi = vc<int>;using vvi = vv<int>; using vvvi = vv<vi>;
using ll = long long;using vl = vc<ll>;using vvl = vv<ll>; using vvvl = vv<vl>;
using ld = long double; using vld = vc<ld>; using vvld = vc<vld>; using vvvld = vc<vvld>;
using uint = unsigned int;
using ull = unsigned long long;
const ld pi = acos(-1.0);
const int inf = 0x3f3f3f3f;
const ll INF = 0x3f3f3f3f3f3f3f3f;
// const ll mod = 1000000007;
const ll mod = 998244353;
inline bool inside(ll y, ll x, ll H, ll W) {return 0 <= (y) and (y) < (H) and 0 <= (x) and (x) < (W); }
 
#define debug(var)  do{std::cout << #var << " : \n";view(var);}while(0)
template<typename T> void view(T e){cout << e << endl;}
template<typename T> void view(const vc<T>& v){for(const auto& e : v){ cout << e << " "; } cout << endl;}
template<typename T> void view(const vv<T>& vv){ for(const auto& v : vv){ view(v); } }

struct modint {
    int Mod = mod;
    int val;
    using mint = modint;
    modint() {};
    modint(ll v) {
        if (0 <= v && v < Mod) val = v;
        else{
            v %= Mod;
            if (v < 0) v += Mod;
            val = v;
        }
    }
    mint operator++(int){
        val++;
        if (val == Mod) val = 0;
        return *this;
    }
    mint operator--(int){
        if (val == 0) val = Mod;
        val--;
        return *this;
    }
    mint& operator+=(const mint& v){
        val += v.val;
        if (val >= Mod) val -= Mod;
        return *this;
    }
    mint& operator-=(const mint& v){
        val -= v.val;
        if (val < 0) val += Mod;
        return *this;
    }
    mint& operator*=(const mint& v){
        val = (int)(1ll * val * v.val % Mod);
        return *this;
    }
    modint inverse() const {
        int a = val, b = mod, u = 1, v = 0, t;
        while (b > 0) {
        t = a / b;
        swap(a -= t * b, b), swap(u -= t * v, v);
        }
        return modint(u);
    }
    mint pow(ll n) const {
        mint a = *this, ret = 1;
        while (n > 0){
            if (n & 1) ret *= a;
            a *= a;
            n >>= 1;
        }
        return ret;
    }
    mint& operator>>=(ll k){
        *this *= mint(2).pow(k).pow(Mod - 2);
        return *this;
    }
    mint& operator<<=(ll k){
        *this *= mint(2).pow(k);
        return *this;
}
    mint operator/=(const mint& v){
        *this *= v.inverse();
        return *this;
    }
    mint operator-() const { return mint(-val);}
    friend mint operator+(const mint& u, const mint& v){return mint(u) += v;}
    friend mint operator-(const mint& u, const mint& v){return mint(u) -= v;}
    friend mint operator*(const mint& u, const mint& v){return mint(u) *= v;}
    friend mint operator/(const mint& u, const mint& v){return mint(u) /= v;}
    friend bool operator==(const mint& u, const mint& v){return u.val == v.val;}
    friend bool operator!=(const mint& u, const mint& v){return u.val != v.val;}
    friend bool operator>(const mint& u, const mint& v){return u.val > v.val;}
    friend bool operator<(const mint& u, const mint& v){return u.val < v.val;}
    friend mint operator>>(mint& u, const ll k){return u >>= k;}
    friend mint operator<<(mint& u, const ll k){return u <<= k;}
    friend ostream& operator<<(ostream& stream, mint& v){
        stream << v.val;
        return stream;
    }
};

using mint = modint;

struct Binoms {
    public : 
        Binoms(int n){
            fact = vc<mint>(1, 1);
            inv_fact = vc<mint>(1, 1);
            update(n);
        };

        void update(int n){
            if (sz >= n) return;
            fact.resize(n + 1, 1);
            inv_fact.resize(n + 1, 1);
            for (int i = sz; i < n; i++) fact[i + 1] = fact[i] * (i + 1);
            inv_fact[n] = 1 / fact[n];
            for (int i = n - 1; i >= sz + 1; i--) inv_fact[i] = inv_fact[i + 1] * (i + 1);
            sz = n;
            return;
        }

        mint C(int n, int k){
            if (n < k || k < 0) return 0;
            if (sz < n) update(n);
            return fact[n] * inv_fact[n - k] * inv_fact[k];
        }

        mint fac(int n){
            if (sz < n) update(n);
            return fact[n];
        }

        mint invfac(int n){
            if (sz < n) update(n);
            return inv_fact[n];
        }

    private :
        int sz = 0;
        vc<mint> fact, inv_fact;
};

int main(){
    int N, M; cin >> N >> M;
    vc<string> S(N);rep(i, N) cin >> S[i];
    vi cnt(3, 0), rcnt(3, 0);
    rep(i, N) rep(j, M){
        if (S[i][j] == 'B') cnt[(i + j) % 3]++;
        if (S[i][j] == '?') rcnt[(i + j) % 3]++;
    }
    mint ans1 = 1, ans2 = 1;
    Binoms B(1);
    rep(i, 3){
        mint f = 0;
        if (cnt[i] % 2){
            for (int j = 1; j <= rcnt[i]; j += 2) f += B.C(rcnt[i], j);
        }else{
            for (int j = 0; j <= rcnt[i]; j += 2) f += B.C(rcnt[i], j);
        }
        ans1 *= f;
    }
    rep(i, 3){
        mint f = 0;
        if (cnt[i] % 2){
            for (int j = 0; j <= rcnt[i]; j += 2) f += B.C(rcnt[i], j);
        }else{
            for (int j = 1; j <= rcnt[i]; j += 2) f += B.C(rcnt[i], j);
        }
        ans2 *= f;
    }
    cout << (ans1 + ans2).val << endl;
}