// #include "my_template.hpp"
// #include "math/static_modint.hpp"
// using mint = mint998;
// #include "math/binomial.hpp"
// Binomial<mint> B;
// using namespace std;
// 
// void solve() {
//     INT(N, M);
//     VEC(string, S, N);
//     vector<int> bcnt(3), qcnt(3);
//     REP(i, N) {
//         REP(j, M) {
//             if (S[i][j] == '?') qcnt[(i + j) % 3]++;
//             if (S[i][j] == 'B') bcnt[(i + j) % 3]++;
//         }
//     }
//     // (x, y, z) にそれぞれ +1 / -1 のどちらか -> 偶奇が常に一致
//     mint ans = 0;
//     mint cnt[3][2] = {};
//     REP(i, 3) REP(x, bcnt[i], bcnt[i] + qcnt[i] + 1) cnt[i][x % 2] += B.C(qcnt[i], x - bcnt[i]);
//     REP(i, 2) ans += cnt[0][i] * cnt[1][i] * cnt[2][i];
//     print(ans);
//     return;
// }
// 
// int main() {
//     solve();
//     return 0;
// }
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cmath>
#include <complex>
#include <deque>
#include <forward_list>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <optional>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

#ifdef RUTHEN_LOCAL
#include <debug.hpp>
#else
#define show(x) true
#endif

// type definition
using i64 = long long;
using u32 = unsigned int;
using u64 = unsigned long long;
using f32 = float;
using f64 = double;
using f128 = long double;
template <class T> using pque = std::priority_queue<T>;
template <class T> using pqueg = std::priority_queue<T, std::vector<T>, std::greater<T>>;
// overload
#define overload4(_1, _2, _3, _4, name, ...) name
#define overload3(_1, _2, _3, name, ...) name
#define overload2(_1, _2, name, ...) name
// for loop
#define REP1(a) for (long long _ = 0; _ < (a); _++)
#define REP2(i, a) for (long long i = 0; i < (a); i++)
#define REP3(i, a, b) for (long long i = (a); i < (b); i++)
#define REP4(i, a, b, c) for (long long i = (a); i < (b); i += (c))
#define REP(...) overload4(__VA_ARGS__, REP4, REP3, REP2, REP1)(__VA_ARGS__)
#define RREP1(a) for (long long _ = (a)-1; _ >= 0; _--)
#define RREP2(i, a) for (long long i = (a)-1; i >= 0; i--)
#define RREP3(i, a, b) for (long long i = (b)-1; i >= (a); i--)
#define RREP(...) overload3(__VA_ARGS__, RREP3, RREP2, RREP1)(__VA_ARGS__)
#define FORE1(x, a) for (auto &&x : a)
#define FORE2(x, y, a) for (auto &&[x, y] : a)
#define FORE3(x, y, z, a) for (auto &&[x, y, z] : a)
#define FORE(...) overload4(__VA_ARGS__, FORE3, FORE2, FORE1)(__VA_ARGS__)
#define FORSUB(t, s) for (long long t = (s); t >= 0; t = (t == 0 ? -1 : (t - 1) & (s)))
// function
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define SORT(a) std::sort((a).begin(), (a).end())
#define RSORT(a) std::sort((a).rbegin(), (a).rend())
#define REV(a) std::reverse((a).begin(), (a).end())
#define UNIQUE(a)                      \
    std::sort((a).begin(), (a).end()); \
    (a).erase(std::unique((a).begin(), (a).end()), (a).end())
#define LEN(a) (int)((a).size())
#define MIN(a) *std::min_element((a).begin(), (a).end())
#define MAX(a) *std::max_element((a).begin(), (a).end())
#define SUM1(a) std::accumulate((a).begin(), (a).end(), 0LL)
#define SUM2(a, x) std::accumulate((a).begin(), (a).end(), (x))
#define SUM(...) overload2(__VA_ARGS__, SUM2, SUM1)(__VA_ARGS__)
#define LB(a, x) std::distance((a).begin(), std::lower_bound((a).begin(), (a).end(), (x)))
#define UB(a, x) std::distance((a).begin(), std::upper_bound((a).begin(), (a).end(), (x)))
template <class T, class U> inline bool chmin(T &a, const U &b) { return (a > T(b) ? a = b, 1 : 0); }
template <class T, class U> inline bool chmax(T &a, const U &b) { return (a < T(b) ? a = b, 1 : 0); }
template <class T, class S> inline T floor(const T x, const S y) {
    assert(y);
    return (y < 0 ? floor(-x, -y) : (x > 0 ? x / y : x / y - (x % y == 0 ? 0 : 1)));
}
template <class T, class S> inline T ceil(const T x, const S y) {
    assert(y);
    return (y < 0 ? ceil(-x, -y) : (x > 0 ? (x + y - 1) / y : x / y));
}
template <class T, class S> std::pair<T, T> inline divmod(const T x, const S y) {
    T q = floor(x, y);
    return {q, x - q * y};
}
// 10 ^ n
constexpr long long TEN(int n) { return (n == 0) ? 1 : 10LL * TEN(n - 1); }
// 1 + 2 + ... + n
#define TRI1(n) ((n) * ((n) + 1LL) / 2)
// l + (l + 1) + ... + r
#define TRI2(l, r) (((l) + (r)) * ((r) - (l) + 1LL) / 2)
#define TRI(...) overload2(__VA_ARGS__, TRI2, TRI1)(__VA_ARGS__)
// bit operation
// bit[i] (= 0 or 1)
#define IBIT(bit, i) (((bit) >> (i)) & 1)
// (0, 1, 2, 3, 4) -> (0, 1, 3, 7, 15)
#define MASK(n) ((1LL << (n)) - 1)
#define POW2(n) (1LL << (n))
// (0, 1, 2, 3, 4) -> (0, 1, 1, 2, 1)
int popcnt(int x) { return __builtin_popcount(x); }
int popcnt(u32 x) { return __builtin_popcount(x); }
int popcnt(i64 x) { return __builtin_popcountll(x); }
int popcnt(u64 x) { return __builtin_popcountll(x); }
// (0, 1, 2, 3, 4) -> (-1, 0, 1, 1, 2)
int topbit(int x) { return (x == 0 ? -1 : 31 - __builtin_clz(x)); }
int topbit(u32 x) { return (x == 0 ? -1 : 31 - __builtin_clz(x)); }
int topbit(i64 x) { return (x == 0 ? -1 : 63 - __builtin_clzll(x)); }
int topbit(u64 x) { return (x == 0 ? -1 : 63 - __builtin_clzll(x)); }
// (0, 1, 2, 3, 4) -> (-1, 0, 1, 0, 2)
int lowbit(int x) { return (x == 0 ? -1 : __builtin_ctz(x)); }
int lowbit(u32 x) { return (x == 0 ? -1 : __builtin_ctz(x)); }
int lowbit(i64 x) { return (x == 0 ? -1 : __builtin_ctzll(x)); }
int lowbit(u64 x) { return (x == 0 ? -1 : __builtin_ctzll(x)); }
// binary search (integer)
template <class T, class F> T bin_search(T ok, T ng, F &f) {
    while ((ok > ng ? ok - ng : ng - ok) > 1) {
        T md = (ng + ok) >> 1;
        (f(md) ? ok : ng) = md;
    }
    return ok;
}
// binary search (real number)
template <class T, class F> T bin_search_real(T ok, T ng, F &f, const int iter = 100) {
    for (int _ = 0; _ < iter; _++) {
        T md = (ng + ok) / 2;
        (f(md) ? ok : ng) = md;
    }
    return ok;
}
// floor(sqrt(x))
template <class T> constexpr T sqrt_floor(T x) { return T(sqrtl(x)); }
// check if [l1, r1) and [l2, r2) intersect
template <class T> constexpr bool intersect(const T l1, const T r1, const T l2, const T r2) { return std::max(l1, l2) < std::min(r1, r2); }
// check if [a.first, a.second) and [b.first, b.second) intersect
template <class T> constexpr bool intersect(const std::pair<T, T> &a, const std::pair<T, T> &b) { return intersect(a.first, a.second, b.first, b.second); }
// rotate matrix counterclockwise by pi / 2
template <class T> void rot(std::vector<std::vector<T>> &a) {
    if ((int)(a.size()) == 0) return;
    if ((int)(a[0].size()) == 0) return;
    int n = (int)(a.size()), m = (int)(a[0].size());
    std::vector res(m, std::vector<T>(n));
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            res[m - 1 - j][i] = a[i][j];
        }
    }
    a.swap(res);
}
// const value
constexpr int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
constexpr int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
// infinity
template <class T> constexpr T INF = 0;
template <> constexpr int INF<int> = 1'000'000'000;                 // 1e9
template <> constexpr i64 INF<i64> = i64(INF<int>) * INF<int> * 2;  // 2e18
template <> constexpr u32 INF<u32> = INF<int>;                      // 1e9
template <> constexpr u64 INF<u64> = INF<i64>;                      // 2e18
template <> constexpr f32 INF<f32> = INF<i64>;                      // 2e18
template <> constexpr f64 INF<f64> = INF<i64>;                      // 2e18
template <> constexpr f128 INF<f128> = INF<i64>;                    // 2e18
// I/O
// input
template <class T> std::istream &operator>>(std::istream &is, std::vector<T> &v) {
    for (auto &&i : v) is >> i;
    return is;
}
template <class... T> void in(T &...a) { (std::cin >> ... >> a); }
void scan() {}
template <class Head, class... Tail> void scan(Head &head, Tail &...tail) {
    in(head);
    scan(tail...);
}
// input macro
#define INT(...)     \
    int __VA_ARGS__; \
    scan(__VA_ARGS__)
#define I64(...)     \
    i64 __VA_ARGS__; \
    scan(__VA_ARGS__)
#define U32(...)     \
    u32 __VA_ARGS__; \
    scan(__VA_ARGS__)
#define U64(...)     \
    u64 __VA_ARGS__; \
    scan(__VA_ARGS__)
#define F32(...)     \
    f32 __VA_ARGS__; \
    scan(__VA_ARGS__)
#define F64(...)     \
    f64 __VA_ARGS__; \
    scan(__VA_ARGS__)
#define F128(...)     \
    f128 __VA_ARGS__; \
    scan(__VA_ARGS__)
#define STR(...)             \
    std::string __VA_ARGS__; \
    scan(__VA_ARGS__)
#define CHR(...)      \
    char __VA_ARGS__; \
    scan(__VA_ARGS__)
#define VEC(type, name, size)     \
    std::vector<type> name(size); \
    scan(name)
#define VEC2(type, name1, name2, size)          \
    std::vector<type> name1(size), name2(size); \
    for (int i = 0; i < size; i++) scan(name1[i], name2[i])
#define VEC3(type, name1, name2, name3, size)                \
    std::vector<type> name1(size), name2(size), name3(size); \
    for (int i = 0; i < size; i++) scan(name1[i], name2[i], name3[i])
#define VEC4(type, name1, name2, name3, name4, size)                      \
    std::vector<type> name1(size), name2(size), name3(size), name4(size); \
    for (int i = 0; i < size; i++) scan(name1[i], name2[i], name3[i], name4[i])
#define VV(type, name, h, w)                       \
    std::vector name((h), std::vector<type>((w))); \
    scan(name)
// output
template <class T> std::ostream &operator<<(std::ostream &os, const std::vector<T> &v) {
    auto n = v.size();
    for (size_t i = 0; i < n; i++) {
        if (i) os << ' ';
        os << v[i];
    }
    return os;
}
template <class... T> void out(const T &...a) { (std::cout << ... << a); }
void print() { out('\n'); }
template <class Head, class... Tail> void print(Head &&head, Tail &&...tail) {
    out(head);
    if (sizeof...(Tail)) out(' ');
    print(tail...);
}
// for interactive problems
void printi() { std::cout << std::endl; }
template <class Head, class... Tail> void printi(Head &&head, Tail &&...tail) {
    out(head);
    if (sizeof...(Tail)) out(' ');
    printi(tail...);
}
// bool output
void YES(bool t = 1) { print(t ? "YES" : "NO"); }
void Yes(bool t = 1) { print(t ? "Yes" : "No"); }
void yes(bool t = 1) { print(t ? "yes" : "no"); }
void NO(bool t = 1) { YES(!t); }
void No(bool t = 1) { Yes(!t); }
void no(bool t = 1) { yes(!t); }
void POSSIBLE(bool t = 1) { print(t ? "POSSIBLE" : "IMPOSSIBLE"); }
void Possible(bool t = 1) { print(t ? "Possible" : "Impossible"); }
void possible(bool t = 1) { print(t ? "possible" : "impossible"); }
void IMPOSSIBLE(bool t = 1) { POSSIBLE(!t); }
void Impossible(bool t = 1) { Possible(!t); }
void impossible(bool t = 1) { possible(!t); }
void FIRST(bool t = 1) { print(t ? "FIRST" : "SECOND"); }
void First(bool t = 1) { print(t ? "First" : "Second"); }
void first(bool t = 1) { print(t ? "first" : "second"); }
void SECOND(bool t = 1) { FIRST(!t); }
void Second(bool t = 1) { First(!t); }
void second(bool t = 1) { first(!t); }
// I/O speed up
struct SetUpIO {
    SetUpIO() {
        std::ios::sync_with_stdio(false);
        std::cin.tie(0);
        std::cout << std::fixed << std::setprecision(20);
    }
} set_up_io;

// constexpr ... for constexpr bool prime()
template <int m> struct StaticModint {
    using mint = StaticModint;
    unsigned int _v;

    static constexpr int mod() { return m; }
    static constexpr unsigned int umod() { return m; }

    constexpr StaticModint() : _v(0) {}

    template <class T> constexpr StaticModint(T v) {
        long long x = (long long)(v % (long long)(umod()));
        if (x < 0) x += umod();
        _v = (unsigned int)(x);
    }

    constexpr unsigned int val() const { return _v; }

    constexpr mint &operator++() {
        _v++;
        if (_v == umod()) _v = 0;
        return *this;
    }
    constexpr mint &operator--() {
        if (_v == 0) _v = umod();
        _v--;
        return *this;
    }
    constexpr mint operator++(int) {
        mint result = *this;
        ++*this;
        return result;
    }
    constexpr mint operator--(int) {
        mint result = *this;
        --*this;
        return result;
    }

    constexpr mint &operator+=(const mint &rhs) {
        _v += rhs._v;
        if (_v >= umod()) _v -= umod();
        return *this;
    }
    constexpr mint &operator-=(const mint &rhs) {
        _v -= rhs._v;
        if (_v >= umod()) _v += umod();
        return *this;
    }
    constexpr mint &operator*=(const mint &rhs) {
        unsigned long long z = _v;
        z *= rhs._v;
        _v = (unsigned int)(z % umod());
        return *this;
    }
    constexpr mint &operator/=(const mint &rhs) { return (*this *= rhs.inv()); }

    constexpr mint operator+() const { return *this; }
    constexpr mint operator-() const { return mint() - *this; }

    constexpr mint pow(long long n) const {
        assert(n >= 0);
        mint x = *this, r = 1;
        while (n) {
            if (n & 1) r *= x;
            x *= x;
            n >>= 1;
        }
        return r;
    }

    constexpr mint inv() const {
        if (prime) {
            assert(_v);
            return pow(umod() - 2);
        } else {
            auto eg = inv_gcd(_v, m);
            assert(eg.first == 1);
            return eg.second;
        }
    }

    friend constexpr mint operator+(const mint &lhs, const mint &rhs) { return mint(lhs) += rhs; }
    friend constexpr mint operator-(const mint &lhs, const mint &rhs) { return mint(lhs) -= rhs; }
    friend constexpr mint operator*(const mint &lhs, const mint &rhs) { return mint(lhs) *= rhs; }
    friend constexpr mint operator/(const mint &lhs, const mint &rhs) { return mint(lhs) /= rhs; }
    friend constexpr bool operator==(const mint &lhs, const mint &rhs) { return lhs._v == rhs._v; }
    friend constexpr bool operator!=(const mint &lhs, const mint &rhs) { return lhs._v != rhs._v; }
    friend std::ostream &operator<<(std::ostream &os, const mint &v) { return os << v.val(); }

    static constexpr bool prime = []() -> bool {
        if (m == 1) return false;
        if (m == 2 || m == 7 || m == 61) return true;
        if (m % 2 == 0) return false;
        unsigned int d = m - 1;
        while (d % 2 == 0) d /= 2;
        for (unsigned int a : {2, 7, 61}) {
            unsigned int t = d;
            mint y = mint(a).pow(t);
            while (t != m - 1 and y != 1 and y != m - 1) {
                y *= y;
                t <<= 1;
            }
            if (y != m - 1 and t % 2 == 0) {
                return false;
            }
        }
        return true;
    }();
    static constexpr std::pair<int, int> inv_gcd(int a, int b) {
        if (a == 0) return {b, 0};
        int s = b, t = a, m0 = 0, m1 = 1;
        while (t) {
            const int u = s / t;
            s -= t * u;
            m0 -= m1 * u;
            std::swap(s, t);
            std::swap(m0, m1);
        }
        if (m0 < 0) m0 += b / s;
        return {s, m0};
    }
};
using mint107 = StaticModint<1000000007>;
using mint998 = StaticModint<998244353>;
using mint = mint998;

// 二項係数ライブラリ
template <class Mint> struct Binomial {
    std::vector<Mint> f, g, h;

    Binomial(const int n_max = 0) {
        f.resize(1, Mint(1));
        g.resize(1, Mint(1));
        h.resize(1, Mint(1));
        if (n_max > 0) extend(n_max);
    }

    // 基本は長さを倍にする
    void extend(int m = -1) {
        const int n = (int)(f.size());  // n >= 1
        if (m == -1) m = n * 2;         // m >= 2
        m = std::min(m, Mint::mod());
        if (n >= m) return;
        f.resize(m);
        g.resize(m);
        h.resize(m);
        // calc f
        for (int i = n; i < m; i++) f[i] = f[i - 1] * Mint(i);
        // calc g
        g[m - 1] = 1 / f[m - 1];
        for (int i = m - 2; i >= n; i--) g[i] = g[i + 1] * Mint(i + 1);
        // calc h
        h[m - 1] = g[m - 1] * f[m - 2];
        for (int i = m - 2; i >= n; i--) h[i] = g[i] * f[i - 1];
    }

    // fact(n) = n!
    Mint fact(const int n) {
        if (n < 0) return Mint(0);
        while (n >= (int)(f.size())) extend();
        return f[n];
    }

    // finv(n) = 1 / n!
    Mint finv(const int n) {
        if (n < 0) return Mint(0);
        while (n >= (int)(g.size())) extend();
        return g[n];
    }

    // inv(n) = 1 / n
    Mint inv(const int n) {
        if (n < 0) return Mint(0);
        while (n >= (int)(h.size())) extend();
    }

    // n C k
    Mint C(const int n, const int k) {
        if (n < 0 or k < 0 or n < k) return Mint(0);
        return fact(n) * finv(n - k) * finv(k);
    }

    // n P k
    Mint P(const int n, const int k) {
        if (n < 0 or k < 0 or n < k) return Mint(0);
        return fact(n) * finv(n - k);
    }

    // n H k
    // n 個から k 個重複を許して取る組合せ
    Mint H(const int n, const int k) {
        if (n < 0 or k < 0) return Mint(0);
        if (k == 0) return Mint(1);
        return C(n + k - 1, k);
    }

    Mint C_naive(int n, int k) {
        if (n < 0 or k < 0 or n < k) return Mint(0);
        Mint res = Mint(1), res_inv = Mint(1);
        k = std::min(k, n - k);
        for (int i = 1; i <= k; i++) {
            res *= (n--);
            res_inv *= i;
        }
        res /= res_inv;
        return res;
    }
};
Binomial<mint> B;
using namespace std;

void solve() {
    INT(N, M);
    VEC(string, S, N);
    vector<int> bcnt(3), qcnt(3);
    REP(i, N) {
        REP(j, M) {
            if (S[i][j] == '?') qcnt[(i + j) % 3]++;
            if (S[i][j] == 'B') bcnt[(i + j) % 3]++;
        }
    }
    // (x, y, z) にそれぞれ +1 / -1 のどちらか -> 偶奇が常に一致
    mint ans = 0;
    mint cnt[3][2] = {};
    REP(i, 3) REP(x, bcnt[i], bcnt[i] + qcnt[i] + 1) cnt[i][x % 2] += B.C(qcnt[i], x - bcnt[i]);
    REP(i, 2) ans += cnt[0][i] * cnt[1][i] * cnt[2][i];
    print(ans);
    return;
}

int main() {
    solve();
    return 0;
}