#line 2 "cp-library/src/cp-template.hpp" #include using namespace std; using ll = long long; using ld = long double; using uint = unsigned int; using ull = unsigned long long; using i128 = __int128_t; template < class T > bool chmin(T& a, T b) { if(a > b) { a = b; return true; } return false; } template < class T > bool chmax(T& a, T b) { if(a < b) { a = b; return true; } return false; } #line 2 "cp-library/src/utility/rep_itr.hpp" template < class T > struct itr { T i, d; constexpr itr(const T i) noexcept : i(i), d(1) {} constexpr itr(const T i, const T d) noexcept : i(i), d(d) {} void operator++() noexcept { i += d; } constexpr int operator*() const noexcept { return i; } constexpr bool operator!=(const itr x) const noexcept { return d > 0 ? i < x.i : i > x.i; } }; template < class T > struct rep { const itr< T > s, t; constexpr rep(const T t) noexcept : s(0), t(t) {} constexpr rep(const T s, const T t) noexcept : s(s), t(t) {} constexpr rep(const T s, const T t, const T d) noexcept : s(s, d), t(t, d) {} constexpr auto begin() const noexcept { return s; } constexpr auto end() const noexcept { return t; } }; template < class T > struct revrep { const itr < T > s, t; constexpr revrep(const T t) noexcept : s(t - 1, -1), t(-1, -1) {} constexpr revrep(const T s, const T t) noexcept : s(t - 1, -1), t(s - 1, -1) {} constexpr revrep(const T s, const T t, const T d) noexcept : s(t - 1, -d), t(s - 1, -d) {} constexpr auto begin() const noexcept { return s; } constexpr auto end() const noexcept { return t; } }; #line 2 "cp-library/src/utility/io.hpp" namespace scanner { struct sca { template < class T > operator T() { T s; cin >> s; return s; } }; struct vec { int n; vec(int n) : n(n) {} template < class T > operator vector< T >() { vector< T > v(n); for(T& x : v) cin >> x; return v; } }; struct mat { int h,w; mat(int h, int w) : h(h), w(w) {} template < class T > operator vector< vector< T > >() { vector m(h, vector< T >(w)); for(vector< T >& v : m) for(T& x : v) cin >> x; return m; } }; struct speedup { speedup() { cin.tie(0); ios::sync_with_stdio(0); } } su; } scanner::sca in() { return scanner::sca(); } scanner::vec in(int n) { return scanner::vec(n); } scanner::mat in(int h, int w) { return scanner::mat(h, w); } namespace printer { void precision(int d) { cout << fixed << setprecision(d); } void flush() { cout.flush(); } } int print() { cout << '\n'; return 0; } template < class head, class... tail > int print(head&& h, tail&&... t) { cout << h; if(sizeof...(tail)) cout << ' '; return print(forward(t)...); } template < class T > int print(vector< T > a, char sep = ' ') { int n = a.size(); for(int i : rep(n)) cout << a[i] << (i != n - 1 ? sep : '\n'); return 0; } template < class T > int print(vector< vector< T > > a) { if(a.empty()) return 0; int h = a.size(), w = a[0].size(); for(int i : rep(h)) for(int j : rep(w)) cout << a[i][j] << (j != w - 1 ? ' ' : '\n'); return 0; } #line 2 "cp-library/src/utility/key_val.hpp" template < class K, class V > struct key_val { K key; V val; key_val() {} key_val(K key, V val) : key(key), val(val) {} }; #line 2 "cp-library/src/utility/vec_op.hpp" template < class T > key_val< int, T > max_of(const vector< T >& a) { int i = max_element(a.begin(), a.end()) - a.begin(); return {i, a[i]}; } template < class T > key_val< int, T > min_of(const vector< T >& a) { int i = min_element(a.begin(), a.end()) - a.begin(); return {i, a[i]}; } template < class T > T sum_of(const vector< T >& a) { T sum = 0; for(const T x : a) sum += x; return sum; } template < class T > vector freq_of(const vector< T >& a, T L, T R) { vector res(R - L); for(const T x : a) res[x - L]++; return res; } template < class T > vector freq_of(const vector< T >& a, T R) { return freq_of(a, T(0), R); } template < class T > struct prefix_sum { vector< T > s; prefix_sum(const vector< T >& a) : s(a) { s.insert(s.begin(), T(0)); for(int i : rep(a.size())) s[i + 1] += s[i]; } // [L, R) T sum(int L, int R) { return s[R] - s[L]; } }; #line 2 "cp-library/src/number/modint.hpp" struct modinfo { uint mod, root, isprime; }; template < modinfo const &ref > struct modint { static constexpr uint const &mod = ref.mod; static constexpr uint const &root = ref.root; static constexpr uint const &isprime = ref.isprime; uint v = 0; constexpr modint& s(uint v) { this->v = v < mod ? v : v - mod; return *this; } constexpr modint(ll v = 0) { s(v % mod + mod); } modint operator-() const { return modint() - *this; } modint& operator+=(const modint& rhs) { return s(v + rhs.v); } modint& operator-=(const modint& rhs) { return s(v + mod - rhs.v); } modint& operator*=(const modint& rhs) { v = ull(v) * rhs.v % mod; return *this; } modint& operator/=(const modint& rhs) { return *this *= inv(rhs); } modint operator+(const modint& rhs) const { return modint(*this) += rhs; } modint operator-(const modint& rhs) const { return modint(*this) -= rhs; } modint operator*(const modint& rhs) const { return modint(*this) *= rhs; } modint operator/(const modint& rhs) const { return modint(*this) /= rhs; } friend modint pow(modint x, ll n) { modint res(1); while(n > 0) { if(n & 1) res *= x; x *= x; n >>= 1; } return res; } friend modint inv(modint v) { if(isprime) { return pow(v, mod - 2); } else { ll a = v.v, b = modint::mod, x = 1, y = 0, t; while(b > 0) { t = a / b; swap(a -= t * b, b); swap(x -= t * y, y); } return modint(x); } } friend modint operator+(int x, const modint& y) { return modint(x) + y; } friend modint operator-(int x, const modint& y) { return modint(x) - y; } friend modint operator*(int x, const modint& y) { return modint(x) * y; } friend modint operator/(int x, const modint& y) { return modint(x) / y; } friend istream& operator>>(istream& is, modint& m) { ll x; is >> x; m = modint(x); return is; } friend ostream& operator<<(ostream& os, const modint& m) { return os << m.v; } bool operator==(const modint& r) const { return v == r.v; } bool operator!=(const modint& r) const { return v != r.v; } static uint get_mod() { return mod; } }; constexpr modinfo base998244353 { 998244353, 3, 1 }; constexpr modinfo base1000000007 { 1000000007, 0, 1 }; using mint998244353 = modint< base998244353 >; using mint1000000007 = modint< base1000000007 >; #line 1 "cp-library/src/number/bicoef.hpp" template < class mint > class bicoef { int N; vector fact_, inv_, finv_; public: bicoef(int N) : N(N), fact_(N+1, 1), inv_(N+1, 1), finv_(N+1, 1) { uint mod = mint::get_mod(); for(int i = 2; i <= N; i++) { fact_[i] = fact_[i - 1] * i; inv_ [i] = - inv_[mod % i] * (mod / i); finv_[i] = finv_[i - 1] * inv_[i]; } } mint fact(int n) { assert(0 <= n && n <= N); return fact_[n]; } mint inv (int n) { assert(0 <= n && n <= N); return inv_ [n]; } mint finv(int n) { assert(0 <= n && n <= N); return finv_[n]; } mint comb(int n, int k) { if(k < 0 || n < k) return mint(0); return fact(n) * finv(k) * finv(n - k); } mint perm(int n, int k) { return fact(n) * finv(n - k); } mint homo(int n, int k) { return comb(n + k - 1, k); } }; #line 4 "B.cpp" int main() { int N = in(), M = in(); using mint = mint998244353; bicoef coef(1e6); mint ans = 0; for(int i = 0; i <= M; i++) ans += coef.comb(i + i - 2, N - 1); print(ans); }