#include <bits/stdc++.h>
#include <atcoder/all>
using mint = atcoder::static_modint<998244353>;
//using mint = atcoder::static_modint<1000000007>;
using namespace std;
using namespace atcoder;
using ld = long double;
using ll = long long;
#define mp(a,b) make_pair(a,b)
#define rep(i,s,n) for(int i=s; i<n; i++)
const vector<int> dx{1,0,-1,0},dy{0,1,0,-1};

vector<mint> factorial(250001,1),invfactorial(250001,1);
mint combi(int n,int r){
    if(n>=r && r>=0)return factorial[n]*invfactorial[r]*invfactorial[n-r];
    else return 0;

}
int main(){
    int n,m;
    cin >> n >> m;
    vector<string> s(n);
    rep(i,0,n)cin >>s[i];
    vector<int> cntbk(3),cnt(3);
    rep(i,0,n)rep(j,0,m)if(s[i][j]=='B')cntbk[(i+j)%3]++;
    rep(i,0,n)rep(j,0,m)if(s[i][j]=='?')cnt[(i+j)%3]++;
    rep(i,1,250001)factorial[i]=factorial[i-1]*i;
    rep(i,1,250001)invfactorial[i]=factorial[i].inv();
    //rep(i,0,3)cout << cntbk[i] << " " << cnt[i] << "\n";
    mint ans=0;
    mint odd=1;
    rep(i,0,3){
        mint s=0;
        rep(j,0,cnt[i]+1)if((j+cntbk[i])&1)s+=combi(cnt[i],j);
        odd*=s;
    }
    mint even=1;
    rep(i,0,3){
        mint s=0;
        rep(j,0,cnt[i]+1)if(((j+cntbk[i])%2==0))s+=combi(cnt[i],j);
        even*=s;
    }
    ans=even+odd;
    cout << ans.val();
}