#include using namespace std; template struct static_modint { using mint = static_modint; public: int val; static_modint() : val(0) {} static_modint(long long v) { if (abs(v) >= mod()) { v %= mod(); } if (v < 0) { v += mod(); } val = v; } mint &operator++() { val++; if (val == mod()) { val = 0; } return *this; } mint &operator--() { if (val == 0) { val = mod(); } val--; return *this; } mint &operator+=(const mint &x) { val += x.val; if (val >= mod()) { val -= mod(); } return *this; } mint &operator-=(const mint &x) { val -= x.val; if (val < 0) { val += mod(); } return *this; } mint &operator*=(const mint &x) { val = (int)((long long)val * x.val % mod()); return *this; } mint &operator/=(const mint &x) { *this *= x.inv(); return *this; } mint operator-() { return mint() - *this; } mint pow(long long n) const { mint x = 1, r = *this; while (n) { if (n & 1) { x *= r; } r *= r; n >>= 1; } return x; } mint inv() const { return pow(mod() - 2); } friend mint operator+(const mint &x, const mint &y) { return mint(x) += y; } friend mint operator-(const mint &x, const mint &y) { return mint(x) -= y; } friend mint operator*(const mint &x, const mint &y) { return mint(x) *= y; } friend mint operator/(const mint &x, const mint &y) { return mint(x) /= y; } friend bool operator==(const mint &x, const mint &y) { return x.val == y.val; } friend bool operator!=(const mint &x, const mint &y) { return x.val != y.val; } friend std::ostream &operator<<(std::ostream &os, const mint &x) { return os << x.val; } friend std::istream &operator>>(std::istream &is, mint &x) { long long v; is >> v; x = mint(v); return is; } private: static constexpr int mod() { return MOD; } }; using mint = static_modint<998244353>; int main() { int c, x; cin >> c >> x; if (x == 0) { cout << mint(c + 1).inv() << endl; return 0; } mint dp[2005]; dp[0] = 1; for (int i = 1;; i++) { if (c + i > x) { mint ans = 1; for (int j = 0; j <= x; j++) { ans -= dp[j] / (x - j + 1); } cout << ans << endl; break; } mint d[2005]{0}; for (int j = 0; j < i; j++) { d[j] += dp[j] * j / (c + i); d[j + 1] += dp[j] * (c + i - j) / (c + i); } swap(dp, d); } }