#include <bits/stdc++.h>
#define rep(i, p, n) for (ll i = p; i < (ll)(n); i++)
#define rep2(i, p, n) for (ll i = p; i >= (ll)(n); i--)
using namespace std;
using ll = long long;
using ld = long double;
const double pi = 3.141592653589793;
const long long inf = 2 * 1e9;
const long long linf = 4 * 1e18;
const ll mod1 = 1000000007;
const ll mod2 = 998244353;
template <class T>
inline bool chmax(T &a, T b)
{    if (a < b)    {        a = b;        return 1;    }    return 0;}
template <class T>
inline bool chmin(T &a, T b)
{
    if (a > b)
    {
        a = b;
        return 1;
    }
    return 0;
}

//atcoder
#include <atcoder/all>
using namespace atcoder;
using mint1 = modint1000000007;
using mint2 = modint998244353;

vector<pair<ll, ll>> base={{-1, 0}, {1, 0}, {0, -1}, {0, 1}};

int main() {
    ll N, M;
    cin >> N >> M;
    vector<string> S(N);
    vector<bool> ch(3), ch2(3);
    rep(i, 0, N) {
        cin >> S.at(i);
    }
    ll co=0, co2=0;
    mint2 ans=1;
    rep(i, 0, N) {
        rep(j, 0, M) {
            if (S.at(i).at(j)=='?') {
                ch.at((i+j)%3)=true;
                co2++;
            }
            if (S.at(i).at(j)=='B') {
                ch2.at((i+j)%3)=!ch2.at((i+j)%3);
            }
        }
    }
    rep(i, 0, 3) {
        if (ch.at(i)) {
            co++;
        }
    }
    if (co>=2) {
        rep(i, 0, co2) {
            ans*=2;
        }
        ans/=4;
        cout << ans.val();
    }
    else if (co==1) {
        rep(i, 0, 3) {
            if (ch.at(i)) {
                if (ch2.at((i+1)%3)==ch2.at((i+2)%3)) {
                    rep(i, 0, co2) {
                        ans*=2;
                    }
                    ans/=2;
                    cout << ans.val();
                }
                else {
                    cout << 0;
                }
            }
        }
    }
    else {
        if (ch2.at(0)==ch2.at(1) && ch2.at(0)==ch2.at(2)) {
            cout << 1;
        }
        else {
            cout << 0;
        }
    }
}