#include <iostream>
#include <vector>
#include <atcoder/convolution>

using mint = atcoder::modint998244353;

int main() {
    int M, N, k, l;
    std::cin >> M >> N >> k >> l;
    M--;

    mint inv = mint(6).inv();
    std::vector<mint> Q(N + 1, 0);
    Q[0] = 1;
    Q[1] = -(k - 1) * inv;
    Q[2] = -(l - k) * inv;
    Q[N] = -(7 - l) * inv;
    std::vector<mint> init(N);
    init[N - 1] = 1;
    std::vector<mint> P = atcoder::convolution(Q, init);
    P.resize(N);

    M += N - 1;
    while (M) {
        std::vector<mint> Q2 = Q;
        for (int i = 1; i <= N; i += 2) {
            Q2[i] = -Q2[i];
        }
        P = atcoder::convolution(P, Q2);
        Q = atcoder::convolution(Q, Q2);

        std::vector<mint> S(N), T(N + 1);
        for (int i = 0; i < N; i++) S[i] = P[i * 2 + (M & 1)];
        for (int i = 0; i <= N; i++) T[i] = Q[i * 2];
        P = S;
        Q = T;
        M >>= 1;
    }

    std::cout << P[0].val() << std::endl;
}