#include<iostream>
#include<sstream>
#include<algorithm>
#include<deque>
#include<list>
#include<map>
#include<memory>
#include<queue>
#include<set>
#include<stack>
#include<utility>
#include<string.h>
#include<string>
#include<math.h>
#include<float.h>
#include<stdio.h>
#include<vector>
#include<iomanip>
#include<bitset>
#include<random>
#include"atcoder/all"
#include"atcoder/modint"
using namespace std;
using namespace atcoder;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<typename T> inline bool chmin(T &a, T b) { return ((a>b) ? (a = b, true) : (false));}
#define rep(i,s,n) for(long long i=s;i<(long long)(n);i++)
#define rrep(i,s,n) for(long long i=n-1;i>=s;i--)
const long long inf = 1LL<<60;
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
//pairのsecondでソートsort(p.begin(),p.end(),cmp)
#define cmp [](pair<ll,ll> a, pair<ll,ll> b){return a.second<b.second;}
//cmpArg := 偏角ソート, atan2l(y, x); atan2l(y, x) = [-pi, pi]
#define cmpArg [](const auto &p1, const auto &p2) { return atan2l(p1.second, p1.first) < atan2l(p2.second, p2.first); }
typedef pair<long long, long long> P;
typedef pair<ll, pair<ll,ll> > PP;
#define rll ll,vector<ll>,greater<ll>
#define rP P,vector<P>,greater<P>
const long double pi = 3.14159265358979;
typedef unsigned long long ull;
#define vll vector<ll>
#define vvll vector<vector<ll>>
#define vmint vector<mint>
#define vvmint vector<vector<mint>>
#define vvch vector<vector<char>>
#define vch vector<char>
#define vstring vector<string>
#define rPP PP,vector<PP>,greater<PP>
#define vP vector<P> 
#define vvP vector<vector<P>>
#define vPP vector<PP>
#define all(x) x.begin(), x.end()
//UNIQUE(x) xをソートして値の被りがないようにする
#define UNIQUE(x) sort(all(x)), x.erase(unique(all(x)), x.end())
int stringcount(string s, char c) { return count(s.cbegin(), s.cend(), c); } //sに含まれるcの数
int pc(ll x) { return __builtin_popcount(x); } //ビット列にどれだけ1がたっているかを求める pop count
//オバフロしない計算はa > inf - b および a > inf / bでとってね

using mint = modint998244353;

const ll MAX = 10101011;
const ll MOD = 998244353;

long long fac[MAX], finv[MAX], inv[MAX];

// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1; //累積積
    finv[0] = finv[1] = 1; //逆元の累積積
    inv[1] = 1; //逆元
    for (int i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}

// 二項係数計算
long long COM(ll n, ll k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}


int main()
{
    ll n,m; cin >> n >> m;
    vvch s(n,vch(m));
    rep(i,0,n) rep(j,0,m) cin >> s[i][j];
    vvll board(n,vll(m,0));
    rep(i,0,n) {
        int cnt = i%3;
        rep(j,0,m) {
            board[i][j] = cnt;
            cnt = (cnt + 1) % 3;
        }
    }
    //0,1,2の黒の偶奇が同じ
    vector<ll> yet(3,0), parity(3,0);
    rep(i,0,n) rep(j,0,m) {
        if(s[i][j] == 'B') parity[board[i][j]]++;
        else if(s[i][j] == '?') yet[board[i][j]]++;
    }

    COMinit();
    mint ans = 0;
    //すべてを0にそろえる
    //rep(i,0,3) cout << i << " " << parity[i] << endl;
    //rep(i,0,3) cout << i << " " << yet[i] << endl;
    mint tmp[3];
    rep(i,0,3) {
        for(ll j=parity[i]%2;j<=yet[i];j+=2) tmp[i] += COM(yet[i], j);
    }
    //cout << tmp[0].val() << " " <<  tmp[1].val() << " " << tmp[2].val() << endl;
    ans += tmp[0] * tmp[1] * tmp[2];
    rep(i,0,3) tmp[i] = 0;
    //すべてを1にそろえる
    rep(i,0,3) {
        for(ll j=(parity[i]+1)%2;j<=yet[i];j+=2) tmp[i] += COM(yet[i], j);
    }
    ans += tmp[0] * tmp[1] * tmp[2];
    cout << ans.val() << endl;
}