#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;
using ll = long long;

#include<atcoder/modint>
using mint = atcoder::modint998244353;

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int n,m;
    cin>>n>>m;
    vector<string> s(n);
    for(int i = 0;i<n;i++) cin>>s[i];
    vector<vector<int>> use;
    vector<vector<int>> vis(n,vector<int>(m,0));
    for(int i = 0;i<n;i++){
        for(int j = 0;j<m;j++){
            if(vis[i][j]) continue;
            int ni = i;
            int nj = j;
            int a = 0;
            int b = 0;
            int c = 0;
            while(true){
                if(ni<0||ni>=n||nj<0||nj>=m) break;
                vis[ni][nj]++;
                if(s[ni][nj]=='W') a++;
                else if(s[ni][nj]=='B') b++;
                else c++;
                ni++;nj--;
            }
            vector<int> now;
            now.push_back(a);
            now.push_back(b);
            now.push_back(c);
            use.push_back(now);
        }
    }

    vector<mint> fac(1001,1),ifac(1001);
    for(int i = 1;i<=1000;i++) fac[i] = fac[i-1] * i;
    for(int i = 0;i<=1000;i++) ifac[i] = fac[i].inv();

    int k = use.size();
    vector<vector<vector<mint>>> dp(k+1,vector<vector<mint>>(2,vector<mint>(2,0)));
    dp[0][0][0] = 1;
    for(int i = 0;i<k;i++){
        int can = use[i][2];
        for(int j = 0;j<=can;j++){
            mint tmp = fac[can] * ifac[j] * ifac[can-j];
            int b = use[i][1] + j;
            b %= 2;
            for(int p = 0;p<2;p++){
                for(int q = 0;q<2;q++){
                    int np = 0;
                    int nb = b + p + q;
                    nb %= 2;
                    if(nb==1) np = 1;
                    dp[i+1][q][np] += dp[i][p][q] * tmp;
                }
            }
        }
    }
    cout<<dp[k][0][0].val()<<endl;

}