#ifndef TEMPLATE_HPP
#define TEMPLATE_HPP

#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>

#define impl_overload4(a, b, c, d, e, ...) e
#define impl_overload5(a, b, c, d, e, f, ...) f
#define impl_overload6(a, b, c, d, e, f, g, ...) g
#define impl_overload7(a, b, c, d, e, f, g, h, ...) h

// clang-format off
#define impl_rep4(i, a, b, c) for (int i = (a); i < (b); i += (c))
#define impl_rep3(i, a, b) impl_rep4(i, a, b, 1)
#define impl_rep2(i, n) impl_rep3(i, 0, n)
#define impl_rep1(n) for (int _ = 0; _ < (n); ++_)
#define rep(...) impl_overload4(__VA_ARGS__, impl_rep4, impl_rep3, impl_rep2, impl_rep1)(__VA_ARGS__)

#define impl_rrep4(i, a, b, c) for (int i = (b) - 1; i >= (a); i -= (c))
#define impl_rrep3(i, a, b) impl_rrep4(i, a, b, 1)
#define impl_rrep2(i, n) impl_rrep3(i, 0, n)
#define rrep(...) impl_overload4(__VA_ARGS__, impl_rrep4, impl_rrep3, impl_rrep2)(__VA_ARGS__)
// clang-format on

#define all(v) std::begin(v), std::end(v)

template<typename T>
constexpr int bit(T x, unsigned int k) {
    return (x >> k) & 1;
}

template<typename T>
constexpr bool chmax(T& a, const T& b) {
    return a < b ? a = b, true : false;
}
template<typename T>
constexpr bool chmin(T& a, const T& b) {
    return a > b ? a = b, true : false;
}

void yesno(bool b) {
    std::cout << (b ? "Yes" : "No") << "\n";
}
void yes() {
    yesno(true);
}
void no() {
    yesno(false);
}

struct Setup {
    Setup() {
        std::ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
        std::cout << std::fixed << std::setprecision(11);
    }
} setup;

#ifdef LOCAL
#include "template_local.hpp"
#else
#define show(...) ((void)0)
#endif

using uint = unsigned int;
using lint = long long;
using ulint = unsigned long long;

using namespace std;

#endif // TEMPLATE_HPP

class mint {
    static const int MOD = 998244353;
    int x;

  public:
    mint(): x(0) {}
    mint(long long y) {
        x = y % MOD;
        if (x < 0) x += MOD;
    }

    mint& operator+=(const mint& m) {
        x += m.x;
        if (x >= MOD) x -= MOD;
        return *this;
    }
    mint& operator-=(const mint& m) {
        x -= m.x;
        if (x < 0) x += MOD;
        return *this;
    }
    mint& operator*=(const mint& m) {
        x = (long long)x * m.x % MOD;
        return *this;
    }
    mint& operator/=(const mint& m) {
        return *this *= inverse(m);
    }
    mint operator+(const mint& m) const {
        return mint(*this) += m;
    }
    mint operator-(const mint& m) const {
        return mint(*this) -= m;
    }
    mint operator*(const mint& m) const {
        return mint(*this) *= m;
    }
    mint operator/(const mint& m) const {
        return mint(*this) /= m;
    }
    mint operator-() const {
        return -x;
    }

    friend mint inverse(const mint& m) {
        int a = m.x, b = MOD, u = 1, v = 0;
        while (b > 0) {
            int t = a / b;
            a -= t * b;
            swap(a, b);
            u -= t * v;
            swap(u, v);
        }
        return u;
    }

    friend istream& operator>>(istream& is, mint& m) {
        long long t;
        is >> t;
        m = t;
        return is;
    }
    friend ostream& operator<<(ostream& os, const mint& m) {
        return os << m.x;
    }
    int to_int() const {
        return x;
    }
};

mint operator+(long long x, const mint& m) {
    return mint(x) + m;
}
mint operator-(long long x, const mint& m) {
    return mint(x) - m;
}
mint operator*(long long x, const mint& m) {
    return mint(x) * m;
}
mint operator/(long long x, const mint& m) {
    return mint(x) / m;
}

mint pow(mint m, long long k) {
    mint res = 1;
    for (; k > 0; k >>= 1, m *= m)
        if (k & 1) res *= m;
    return res;
}

mint factorial(int n) {
    static vector<mint> memo = {1};
    if (memo.size() <= n) {
        int k = memo.size();
        memo.resize(n + 1);
        for (; k <= n; k++) memo[k] = memo[k - 1] * k;
    }
    return memo[n];
}

mint factorial_inverse(int n) {
    static vector<mint> memo = {1};
    if (memo.size() <= n) {
        int k = memo.size();
        memo.resize(n + 1);
        memo[n] = inverse(factorial(n));
        for (int i = n; i > k; i--) memo[i - 1] = memo[i] * i;
    }
    return memo[n];
}

mint choose(int n, int k, int type = 0) {
    if (k == 0) return 1;
    if (n < k) return 0;
    if (type == 0) {
        return factorial(n) * factorial_inverse(k) * factorial_inverse(n - k);
    }
    else {
        if (k > n - k) k = n - k;
        mint res = factorial_inverse(k);
        rep (i, k) res *= n - i;
        return res;
    }
}

mint multichoose(int n, int k, int type = 0) {
    return choose(n + k - 1, k, type);
}

int main() {
    int a, b;
    cin >> a >> b;
    cout << choose(a + b - 2, a - 1) << endl;
    return 0;
}