#include <cassert>
#include <iostream>
#include <vector>
using namespace std;

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

template <typename modint> struct acl_fac {
    std::vector<modint> facs, facinvs;
    acl_fac(int N) {
        assert(-1 <= N and N < modint::mod());
        facs.resize(N + 1, 1);
        for (int i = 1; i <= N; i++) facs[i] = facs[i - 1] * i;
        facinvs.assign(N + 1, facs.back().inv());
        for (int i = N; i > 0; i--) facinvs[i - 1] = facinvs[i] * i;
    }
    modint ncr(int n, int r) const {
        if (n < 0 or r < 0 or n < r) return 0;
        return facs[n] * facinvs[r] * facinvs[n - r];
    }
    modint operator[](int i) const { return facs[i]; }
    modint finv(int i) const { return facinvs[i]; }
};
acl_fac<mint> fac(1000000);

// https://hitonanode.github.io/cplib-cpp/formal_power_series/coeff_of_rational_function.hpp

// Calculate [x^N](num(x) / den(x))
// - Coplexity: O(LlgLlgN) ( L = size(num) + size(den) )
// - Reference: `Bostan–Mori algorithm` <https://qiita.com/ryuhe1/items/da5acbcce4ac1911f47a>
template <typename Tp> Tp coefficient_of_rational_function(long long N, std::vector<Tp> num, std::vector<Tp> den) {
    assert(N >= 0);
    while (den.size() and den.back() == 0) den.pop_back();
    assert(den.size());
    int h = 0;
    while (den[h] == 0) h++;
    N += h;
    den.erase(den.begin(), den.begin() + h);

    if (den.size() == 1) return N < int(num.size()) ? num[N] / den[0] : 0;

    while (N) {
        std::vector<Tp> g = den;
        for (size_t i = 1; i < g.size(); i += 2) { g[i] = -g[i]; }
        auto conv_num_g = atcoder::convolution(num, g);
        num.resize((conv_num_g.size() + 1 - (N & 1)) / 2);
        for (size_t i = 0; i < num.size(); i++) { num[i] = conv_num_g[i * 2 + (N & 1)]; }
        auto conv_den_g = atcoder::convolution(den, g);
        for (size_t i = 0; i < den.size(); i++) { den[i] = conv_den_g[i * 2]; }
        N >>= 1;
    }
    return num[0] / den[0];
}

int main() {
    // [x^M] ((1 + 2x)^(N + 1) - (x - x^2)^(N + 1)) / ((1 - x)^(N + 1) (1 + x + x^2))
    int N, M;
    cin >> N >> M;
    vector<mint> num(N * 2 + 3), den(N + 4);
    for (int d = 0; d <= N + 1; ++d) {
        mint ncr = fac.ncr(N + 1, d);
        mint sgn = d % 2 ? -1 : 1;
        num[d] += mint(2).pow(d) * ncr;
        num[d * 2 + (N + 1 - d)] -= sgn * ncr;
        den[d] += ncr * sgn;
        den[d + 1] += ncr * sgn;
        den[d + 2] += ncr * sgn;
    }
    cout << coefficient_of_rational_function(M, num, den).val() << '\n';
}