#ifdef t9unkubj
#include"template.h"
//#include"template_no_debug.h"
#else
#undef _GLIBCXX_DEBUG
#pragma GCC optimize("O3")
#define dbg(...) 199958
using namespace std;
#include<bits/stdc++.h>
using uint=unsigned;
using ll=long long;
using ull=unsigned long long;
using ld=long double;
using pii=pair<int,int>;
using pll=pair<ll,ll>;
template<class T>using vc=vector<T>;
template<class T>using vvc=vc<vc<T>>;
template<class T>using vvvc=vvc<vc<T>>;
using vi=vc<int>;
using vvi=vc<vi>;
using vvvi=vc<vvi>;
using vl=vc<ll>;
using vvl=vc<vl>;
using vvvl=vc<vvl>;
template<class T>using smpq=priority_queue<T,vector<T>,greater<T>>;
template<class T>using bipq=priority_queue<T>;
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define REP(i,j,n) for(ll i=(j);i<(ll)(n);i++)
#define DREP(i,n,m) for(ll i=(n);i>=(m);i--)
#define drep(i,n) for(ll i=((n)-1);i>=0;i--)
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define is insert
#define bg begin()
#define ed end()
void scan(int&a) { cin >> a; }
void scan(ll&a) { cin >> a; }
void scan(string&a) { cin >> a; }
void scan(char&a) { cin >> a; }
void scan(uint&a) { cin >> a; }
void scan(ull&a) { cin >> a; }
void scan(bool&a) { cin >> a; }
void scan(ld&a){ cin>> a;}
template<class T> void scan(vector<T>&a) { for(auto&x:a) scan(x); }
void read() {}
template<class Head, class... Tail> void read(Head&head, Tail&... tail) { scan(head); read(tail...); }
#define INT(...) int __VA_ARGS__; read(__VA_ARGS__);
#define LL(...) ll __VA_ARGS__; read(__VA_ARGS__);
#define ULL(...) ull __VA_ARGS__; read(__VA_ARGS__);
#define STR(...) string __VA_ARGS__; read(__VA_ARGS__);
#define CHR(...) char __VA_ARGS__; read(__VA_ARGS__);
#define DBL(...) double __VA_ARGS__; read(__VA_ARGS__);
#define LD(...) ld __VA_ARGS__; read(__VA_ARGS__);
#define VC(type, name, ...) vector<type> name(__VA_ARGS__); read(name);
#define VVC(type, name, size, ...) vector<vector<type>> name(size, vector<type>(__VA_ARGS__)); read(name);
void print(int a) { cout << a; }
void print(ll a) { cout << a; }
void print(string a) { cout << a; }
void print(char a) { cout << a; }
void print(uint a) { cout << a; }
void print(bool a) { cout << a; }
void print(ull a) { cout << a; }
void print(double a) { cout << a; }
void print(ld a){ cout<< a; }
template<class T> void print(vector<T>a) { for(int i=0;i<(int)a.size();i++){if(i)cout<<" ";print(a[i]);}cout<<endl;}
void PRT() { cout <<endl; return ; }
template<class T> void PRT(T a) { print(a); cout <<endl; return; }
template<class Head, class... Tail> void PRT(Head head, Tail ... tail) { print(head); cout << " "; PRT(tail...); return; }
template<class T,class F>
bool chmin(T &x, F y){
    if(x>y){
        x=y;
        return true;
    }
    return false;
}
template<class T, class F>
bool chmax(T &x, F y){
    if(x<y){
        x=y;
        return true;
    }
    return false;
}
void YesNo(bool b){
    cout<<(b?"Yes":"No")<<endl;
}
void Yes(){
    cout<<"Yes"<<endl;
}
void No(){
    cout<<"No"<<endl;
}
template<class T>
int popcount(T n){
    return __builtin_popcountll(n);
}
template<class T>
T sum(vc<T>&a){
    return accumulate(all(a),T(0));
}
template<class T>
T max(vc<T>&a){
    return *max_element(all(a));
}
template<class T>
T min(vc<T>&a){
    return *min_element(all(a));
}
template<class T>
void unique(vc<T>&a){
    a.erase(unique(all(a)),a.end());
}
vvi readgraph(int n,int m,int off = -1){
    vvi g(n);
    rep(i, m){
        int u,v;
        cin>>u>>v;
        u+=off,v+=off;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    return g;
}
vvi readtree(int n,int off=-1){
    return readgraph(n,n-1,off);
}
template<class T>
vc<T> presum(vc<T> &a){
    vc<T> ret(a.size()+1);
    rep(i,a.size())ret[i+1]=ret[i]+a[i];
    return ret;
}
template<class T, class F>
vc<T> &operator+=(vc<T> &a,F b){
    for (auto&v:a)v += b;
    return a;
}
template<class T, class F>
vc<T> &operator-=(vc<T>&a,F b){
    for (auto&v:a)v-=b;
    return a;
}
template<class T, class F>
vc<T> &operator*=(vc<T>&a,F b){
    for (auto&v:a)v*=b;
    return a;
}
#endif
template<class T,class G,class F>
F modpow(T x,G p,F m){
    T ret=1%m;
    x%=m;
    while(p){
        if(p&1)ret=(1ll*ret*x)%m;
        x=(1ll*x*x)%m;
        p>>=1;
    }
    return ret;
}
template<class T>
T extgcd(T a,T b,T&x,T&y){//ax+by=gcd(a,b)となるようなもの
    if(b==0){
        x=1;
        y=0;
        return a;
    }else{
        T res=extgcd(b,a%b,y,x);
        y-=(a/b)*x;
        return res;
    }
}
template<class T>
pair<T,T> inv(T x,T m){
    T a1,a2;
    T res=extgcd(x,m,a1,a2);
    return {a1,m/res};
}
constexpr int mod=998244353;
struct mint{
    long long val;
    inline long long fast(long long x){
        if(x<mod&&x>=0)return x;
        x%=mod;
        if(x<0)x+=mod;
        return x;
    }
    mint():val(0){}
    mint(long long val):val(fast(val)){}
    mint power(long long m)const {
        mint res(1);
        mint ret(*this);
        while(m){
           if(m&1)res*=ret;
           ret*=ret;
           m>>=1;
        }
        return res;
    }
    mint& operator++() {
        val++;
        if (val == mod) val = 0;
        return *this;
    }
    mint& operator--() {
        if (val == 0)val=mod;
        val--;
        return *this;
    }
    mint operator++(int) {
        mint result = *this;
        ++*this;
        return result;
    }
    mint operator--(int) {
        mint result = *this;
        --*this;
        return result;
    }
    mint operator-() const { 
      return mint(-val);
    }
    friend mint operator +(const mint&a,const mint&b) noexcept{
        return mint(a)+=b;
    }
    friend mint operator -(const mint&a,const mint&b) noexcept{
        return mint(a)-=b;
    }
    friend mint operator *(const mint&a,const mint&b) noexcept{
        return mint(a)*=b;
    }
    friend mint operator /(const mint&a,const mint&b) noexcept{
        return mint(a)/=b;
    }
    mint& operator+=(const mint&a)noexcept{
        val+=a.val;
        if(val>=mod)val-=mod;
        return *this;
    }
    mint& operator-=(const mint&a)noexcept{
        val-=a.val;
        if(val<0)val+=mod;
        return *this;
    }
    mint& operator*=(const mint&a){
        val*=a.val;
        val=fast(val);
        return *this;
    }
    mint& operator/=(const mint&a){
        val*=inv<long long>(a.val,mod).first;
        val=fast(val);
        return *this;
    }
    bool operator == (const mint&x)const noexcept{
        return this->val==x.val;
    }
    bool operator != (const mint&x)const noexcept{
        return this->val!=x.val;
    }
    friend ostream& operator << (ostream &os, const mint &x) noexcept {
        return os << x.val;
    }
    friend istream& operator >> (istream &is,  mint &x) noexcept {
        long long v;
        is >> v;
        x=mint(v);
        return is;
    }
};
vector<mint>fact(1,1),invfact(1,1);
void build(int n){
    if(n<(int)fact.size())return;
    fact=invfact=vector<mint>(n+1);
    fact[0]=1;
    for(int i=1;i<=n;i++)fact[i]=fact[i-1]*i;
    invfact[n]=(1/fact[n]);
    for(int i=n-1;i>=0;i--)invfact[i]=invfact[i+1]*(i+1);
}
mint C(int a,int b){//aCb
    if(a<0||b<0||a-b<0)return mint(0);
    while((int)fact.size()<=a){
        fact.push_back(fact.back()*(fact.size()));
    }
    while((int)invfact.size()<=a){
        invfact.push_back(invfact.back()/invfact.size());
    }
    return fact[a]*invfact[b]*invfact[a-b];
}
mint P(int a,int b){
    if(a<b||b<0)return 0;
    return fact[a]*invfact[a-b];
}
//a個のものからb個を重複を許して選ぶ
mint H(int a,int b){
    return C(a+b-1,b);
}
void print(mint a) { cout << a; }
template<class T>
pair<T,T> mod_solve(T a,T b,T m){//ax=b mod mとなるxを返す
    a%=m,b%=m;if(a<0)a+=m;if(b<0)b+=m;
    T g=gcd(gcd(a,b),m);
    a/=g,b/=g,m/=g;
    if(gcd(a,m)>1)return {-1,-1};
    return {(inv(a,m).first*b)%m,inv(a,m).second};
}
double pass_time=0;
void solve(){
    INT(n,m);
    VC(string,s,n);
    vvc<char> t(3);
    rep(i,n)rep(j,m){
        t[(i+j)%3].pb(s[i][j]);
    }
    mint odd=1;
    mint even=1;
    rep(i,3){
        map<char,int>ma;
        for(auto x:t[i]){
            ma[x]++;
        }
        mint a1=0,a2=0;
        rep(j,ma['?']+1){
            ((j+ma['B'])%2?a1:a2)+=C(ma['?'],j);
        }
        odd*=a1,even*=a2;
    }
    PRT(even+odd);
}
signed main(){
    cin.tie(0)->sync_with_stdio(0);
    pass_time=clock();
    int t=1;
    //cin>>t;
    while(t--)solve();
    pass_time=clock()-pass_time;
    dbg(pass_time/CLOCKS_PER_SEC);
}