#include <bits/stdc++.h>

using namespace std;

template<class F, class S>
ostream &operator<<(ostream &s, const pair<F, S> &v) {
    s << "(" << v.first << ", " << v.second << ")";
    return s;
}
template<ranges::range T> requires (!is_convertible_v<T, string_view>)
istream &operator>>(istream &s, T &&v) { 
    for (auto &&x : v) s >> x; 
    return s; 
}
template<ranges::range T> requires (!is_convertible_v<T, string_view>)
ostream &operator<<(ostream &s, T &&v) { 
    for (auto &&x : v) s << x << ' '; 
    return s; 
}

#ifdef LOCAL
template<class... T> void dbg(T... x) {
    char e{};
    ((cerr << e << x, e = ' '), ...);
}
#define debug(x...) dbg(#x, '=', x, '\n')
#else
#define debug(...) ((void)0)
#endif

#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define ff first
#define ss second

template<class T> inline constexpr T inf = numeric_limits<T>::max() / 2;
bool chmin(auto &a, auto b) { return (b < a and (a = b, true)); }
bool chmax(auto &a, auto b) { return (a < b and (a = b, true)); }

using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
using i128 = __int128;
using u128 = unsigned __int128;

constexpr i64 mod = 998244353;

template<class T>
constexpr T power(T a, i64 b) {
    T res = 1;
    for (; b; b /= 2, a *= a) {
        if (b % 2) {
            res *= a;
        }
    }
    return res;
}

template<int P = mod>
struct MInt {
    int x;
    constexpr MInt() : x{} {}
    constexpr MInt(i64 x) : x{norm(x % getMod())} {}
    
    static int Mod;
    constexpr static int getMod() {
        if (P > 0) {
            return P;
        } else {
            return Mod;
        }
    }
    constexpr static void setMod(int Mod_) {
        Mod = Mod_;
    }
    constexpr int norm(int x) const {
        if (x < 0) {
            x += getMod();
        }
        if (x >= getMod()) {
            x -= getMod();
        }
        return x;
    }
    constexpr int val() const {
        return x;
    }
    explicit constexpr operator int() const {
        return x;
    }
    constexpr MInt operator-() const {
        MInt res;
        res.x = norm(getMod() - x);
        return res;
    }
    constexpr MInt inv() const {
        assert(x != 0);
        return power(*this, getMod() - 2);
    }
    constexpr MInt &operator*=(MInt rhs) & {
        x = 1LL * x * rhs.x % getMod();
        return *this;
    }
    constexpr MInt &operator+=(MInt rhs) & {
        x = norm(x + rhs.x);
        return *this;
    }
    constexpr MInt &operator-=(MInt rhs) & {
        x = norm(x - rhs.x);
        return *this;
    }
    constexpr MInt &operator/=(MInt rhs) & {
        return *this *= rhs.inv();
    }
    friend constexpr MInt operator*(MInt lhs, MInt rhs) {
        MInt res = lhs;
        res *= rhs;
        return res;
    }
    friend constexpr MInt operator+(MInt lhs, MInt rhs) {
        MInt res = lhs;
        res += rhs;
        return res;
    }
    friend constexpr MInt operator-(MInt lhs, MInt rhs) {
        MInt res = lhs;
        res -= rhs;
        return res;
    }
    friend constexpr MInt operator/(MInt lhs, MInt rhs) {
        MInt res = lhs;
        res /= rhs;
        return res;
    }
    friend constexpr std::istream &operator>>(std::istream &is, MInt &a) {
        i64 v;
        is >> v;
        a = MInt(v);
        return is;
    }
    friend constexpr std::ostream &operator<<(std::ostream &os, const MInt &a) {
        return os << a.val();
    }
    friend constexpr bool operator==(MInt lhs, MInt rhs) {
        return lhs.val() == rhs.val();
    }
    friend constexpr bool operator!=(MInt lhs, MInt rhs) {
        return lhs.val() != rhs.val();
    }
};

template<>
int MInt<0>::Mod = 1;

template<int V, int P>
constexpr MInt<P> CInv = MInt<P>(V).inv();

constexpr int P = 998244353;
using Z = MInt<P>;

std::vector<int> rev;
template<int P>
std::vector<MInt<P>> roots{0, 1};

template<int P>
constexpr MInt<P> findPrimitiveRoot() {
    MInt<P> i = 2;
    int k = __builtin_ctz(P - 1);
    while (true) {
        if (power(i, (P - 1) / 2) != 1) {
            break;
        }
        i += 1;
    }
    return power(i, (P - 1) >> k);
}

template<int P>
constexpr MInt<P> primitiveRoot = findPrimitiveRoot<P>();

template<>
constexpr MInt<998244353> primitiveRoot<998244353> {31};

template<int P>
constexpr void dft(std::vector<MInt<P>> &a) {
    int n = a.size();
    
    if (int(rev.size()) != n) {
        int k = __builtin_ctz(n) - 1;
        rev.resize(n);
        for (int i = 0; i < n; i++) {
            rev[i] = rev[i >> 1] >> 1 | (i & 1) << k;
        }
    }
    
    for (int i = 0; i < n; i++) {
        if (rev[i] < i) {
            std::swap(a[i], a[rev[i]]);
        }
    }
    if (roots<P>.size() < n) {
        int k = __builtin_ctz(roots<P>.size());
        roots<P>.resize(n);
        while ((1 << k) < n) {
            auto e = power(primitiveRoot<P>, 1 << (__builtin_ctz(P - 1) - k - 1));
            for (int i = 1 << (k - 1); i < (1 << k); i++) {
                roots<P>[2 * i] = roots<P>[i];
                roots<P>[2 * i + 1] = roots<P>[i] * e;
            }
            k++;
        }
    }
    for (int k = 1; k < n; k *= 2) {
        for (int i = 0; i < n; i += 2 * k) {
            for (int j = 0; j < k; j++) {
                MInt<P> u = a[i + j];
                MInt<P> v = a[i + j + k] * roots<P>[k + j];
                a[i + j] = u + v;
                a[i + j + k] = u - v;
            }
        }
    }
}

template<int P>
constexpr void idft(std::vector<MInt<P>> &a) {
    int n = a.size();
    std::reverse(a.begin() + 1, a.end());
    dft(a);
    MInt<P> inv = (1 - P) / n;
    for (int i = 0; i < n; i++) {
        a[i] *= inv;
    }
}

template<int P = 998244353>
struct Poly : public std::vector<MInt<P>> {
    using Value = MInt<P>;
    
    Poly() : std::vector<Value>() {}
    explicit constexpr Poly(int n) : std::vector<Value>(n) {}
    
    explicit constexpr Poly(const std::vector<Value> &a) : std::vector<Value>(a) {}
    constexpr Poly(const std::initializer_list<Value> &a) : std::vector<Value>(a) {}
    
    template<class InputIt, class = std::_RequireInputIter<InputIt>>
    explicit constexpr Poly(InputIt first, InputIt last) : std::vector<Value>(first, last) {}
    
    template<class F>
    explicit constexpr Poly(int n, F f) : std::vector<Value>(n) {
        for (int i = 0; i < n; i++) {
            (*this)[i] = f(i);
        }
    }
    
    constexpr Poly shift(int k) const {
        if (k >= 0) {
            auto b = *this;
            b.insert(b.begin(), k, 0);
            return b;
        } else if (this->size() <= -k) {
            return Poly();
        } else {
            return Poly(this->begin() + (-k), this->end());
        }
    }
    constexpr Poly trunc(int k) const {
        Poly f = *this;
        f.resize(k);
        return f;
    }
    constexpr friend Poly operator+(const Poly &a, const Poly &b) {
        Poly res(std::max(a.size(), b.size()));
        for (int i = 0; i < a.size(); i++) {
            res[i] += a[i];
        }
        for (int i = 0; i < b.size(); i++) {
            res[i] += b[i];
        }
        return res;
    }
    constexpr friend Poly operator-(const Poly &a, const Poly &b) {
        Poly res(std::max(a.size(), b.size()));
        for (int i = 0; i < a.size(); i++) {
            res[i] += a[i];
        }
        for (int i = 0; i < b.size(); i++) {
            res[i] -= b[i];
        }
        return res;
    }
    constexpr friend Poly operator-(const Poly &a) {
        std::vector<Value> res(a.size());
        for (int i = 0; i < int(res.size()); i++) {
            res[i] = -a[i];
        }
        return Poly(res);
    }
    constexpr friend Poly operator*(Poly a, Poly b) {
        if (a.size() == 0 || b.size() == 0) {
            return Poly();
        }
        if (a.size() < b.size()) {
            std::swap(a, b);
        }
        int n = 1, tot = a.size() + b.size() - 1;
        while (n < tot) {
            n *= 2;
        }
        if (((P - 1) & (n - 1)) != 0 || b.size() < 128) {
            Poly c(a.size() + b.size() - 1);
            for (int i = 0; i < a.size(); i++) {
                for (int j = 0; j < b.size(); j++) {
                    c[i + j] += a[i] * b[j];
                }
            }
            return c;
        }
        a.resize(n);
        b.resize(n);
        dft(a);
        dft(b);
        for (int i = 0; i < n; ++i) {
            a[i] *= b[i];
        }
        idft(a);
        a.resize(tot);
        return a;
    }
    constexpr friend Poly operator*(Value a, Poly b) {
        for (int i = 0; i < int(b.size()); i++) {
            b[i] *= a;
        }
        return b;
    }
    constexpr friend Poly operator*(Poly a, Value b) {
        for (int i = 0; i < int(a.size()); i++) {
            a[i] *= b;
        }
        return a;
    }
    constexpr friend Poly operator/(Poly a, Value b) {
        for (int i = 0; i < int(a.size()); i++) {
            a[i] /= b;
        }
        return a;
    }
    constexpr Poly &operator+=(Poly b) {
        return (*this) = (*this) + b;
    }
    constexpr Poly &operator-=(Poly b) {
        return (*this) = (*this) - b;
    }
    constexpr Poly &operator*=(Poly b) {
        return (*this) = (*this) * b;
    }
    constexpr Poly &operator*=(Value b) {
        return (*this) = (*this) * b;
    }
    constexpr Poly &operator/=(Value b) {
        return (*this) = (*this) / b;
    }
    constexpr Poly deriv() const {
        if (this->empty()) {
            return Poly();
        }
        Poly res(this->size() - 1);
        for (int i = 0; i < this->size() - 1; ++i) {
            res[i] = (i + 1) * (*this)[i + 1];
        }
        return res;
    }
    constexpr Poly integr() const {
        Poly res(this->size() + 1);
        for (int i = 0; i < this->size(); ++i) {
            res[i + 1] = (*this)[i] / (i + 1);
        }
        return res;
    }
    constexpr Poly inv(int m) const {
        Poly x{(*this)[0].inv()};
        int k = 1;
        while (k < m) {
            k *= 2;
            x = (x * (Poly{2} - trunc(k) * x)).trunc(k);
        }
        return x.trunc(m);
    }
    constexpr Poly log(int m) const {
        return (deriv() * inv(m)).integr().trunc(m);
    }
    constexpr Poly exp(int m) const {
        Poly x{1};
        int k = 1;
        while (k < m) {
            k *= 2;
            x = (x * (Poly{1} - x.log(k) + trunc(k))).trunc(k);
        }
        return x.trunc(m);
    }
    constexpr Poly pow(int k, int m) const {
        int i = 0;
        while (i < this->size() && (*this)[i] == 0) {
            i++;
        }
        if (i == this->size() || 1LL * i * k >= m) {
            return Poly(m);
        }
        Value v = (*this)[i];
        auto f = shift(-i) * v.inv();
        return (f.log(m - i * k) * k).exp(m - i * k).shift(i * k) * power(v, k);
    }
    constexpr Poly sqrt(int m) const {
        Poly x{1};
        int k = 1;
        while (k < m) {
            k *= 2;
            x = (x + (trunc(k) * x.inv(k)).trunc(k)) * CInv<2, P>;
        }
        return x.trunc(m);
    }
    constexpr Poly mulT(Poly b) const {
        if (b.size() == 0) {
            return Poly();
        }
        int n = b.size();
        std::reverse(b.begin(), b.end());
        return ((*this) * b).shift(-(n - 1));
    }
};

void solve() {
    i64 n, m;
    cin >> n >> m;

    Poly G(n + 1);
    for (int i = 1; i <= n; i++) {
        if (i % 3 != 0) {
            G[i] = Z((i / 3) % 2 ? -1 : 1);
        }
        G[i] *= Z(m + 1 - i);
    }

    cout << (Poly{Z(1)} - G).inv(n + 1)[n] << '\n';
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    int t = 1;
    // cin >> t;

    while (t--) {
        solve();
    }

    return 0;
}