#define LOCAL #define _USE_MATH_DEFINES #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; template ostream& operator <<(ostream& out, const pair& a) { out << "(" << a.first << "," << a.second << ")"; return out; } template ostream& operator <<(ostream& out, const array& a) { out << "["; bool first = true; for (auto& v : a) { out << (first ? "" : ", "); out << v; first = 0;} out << "]"; return out; } template ostream& operator <<(ostream& out, const vector& a) { out << "["; bool first = true; for (auto v : a) { out << (first ? "" : ", "); out << v; first = 0;} out << "]"; return out; } template ostream& operator <<(ostream& out, const set& a) { out << "{"; bool first = true; for (auto& v : a) { out << (first ? "" : ", "); out << v; first = 0;} out << "}"; return out; } template ostream& operator <<(ostream& out, const multiset& a) { out << "{"; bool first = true; for (auto& v : a) { out << (first ? "" : ", "); out << v; first = 0;} out << "}"; return out; } template ostream& operator <<(ostream& out, const map& a) { out << "{"; bool first = true; for (auto& p : a) { out << (first ? "" : ", "); out << p.first << ":" << p.second; first = 0;} out << "}"; return out; } #ifdef LOCAL #define trace(...) __f(#__VA_ARGS__, __VA_ARGS__) #else #define trace(...) 42 #endif template void __f(const char* name, Arg1&& arg1){ cerr << name << ": " << arg1 << endl; } template void __f(const char* names, Arg1&& arg1, Args&&... args){ const char* comma = strchr(names + 1, ','); cerr.write(names, comma - names) << ": " << arg1 << " |"; __f(comma + 1, args...); } template auto vect(const T& v, int n) { return vector(n, v); } template auto vect(const T& v, int n, D... m) { return vector(n, vect(v, m...)); } using int64 = long long; using int128 = __int128_t; using ii = pair; #define SZ(x) (int)((x).size()) template static constexpr T inf = numeric_limits::max() / 2; // const int MOD = 1e9 + 7; const int MOD = 998244353; // mt19937 mrand(random_device{}()); // int rnd(int x) { return mrand() % x; } mt19937_64 mrand(random_device{}()); int64 rnd(int64 x) { return mrand() % x; } int lg2(int64 x) { return sizeof(int64) * 8 - 1 - __builtin_clzll(x); } template void out(const vector& a) { for (int i = 0; i < SZ(a); ++i) cout << a[i] << " \n"[i + 1 == SZ(a)]; } template bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; } template bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; } template void dedup(vector& v) { sort(v.begin(), v.end()); v.erase(unique(v.begin(), v.end()), v.end()); } void add_mod(int& x, int y) { x += y; if (x >= MOD) x -= MOD; } void sub_mod(int& x, int y) { x += MOD - y; if (x >= MOD) x -= MOD; } struct fast_ios { fast_ios() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(10); }; } fast_ios_; template struct modnum { static constexpr int MOD = MOD_; static_assert(MOD_ > 0, "MOD must be positive"); private: int v; static int minv(int a, int m) { a %= m; assert(a); return a == 1 ? 1 : int(m - int64(minv(m, a)) * int64(m) / a); } public: modnum() : v(0) {} modnum(int64 v_) : v(int(v_ % MOD)) { if (v < 0) v += MOD; } explicit operator int() const { return v; } friend std::ostream& operator << (std::ostream& out, const modnum& n) { return out << int(n); } friend std::istream& operator >> (std::istream& in, modnum& n) { int64 v_; in >> v_; n = modnum(v_); return in; } friend bool operator == (const modnum& a, const modnum& b) { return a.v == b.v; } friend bool operator != (const modnum& a, const modnum& b) { return a.v != b.v; } modnum inv() const { modnum res; res.v = minv(v, MOD); return res; } friend modnum inv(const modnum& m) { return m.inv(); } modnum neg() const { modnum res; res.v = v ? MOD-v : 0; return res; } friend modnum neg(const modnum& m) { return m.neg(); } modnum operator- () const { return neg(); } modnum operator+ () const { return modnum(*this); } modnum& operator ++ () { ++v; if (v == MOD) v = 0; return *this; } modnum& operator -- () { if (v == 0) v = MOD; --v; return *this; } modnum& operator += (const modnum& o) { v += o.v; if (v >= MOD) v -= MOD; return *this; } modnum& operator -= (const modnum& o) { v -= o.v; if (v < 0) v += MOD; return *this; } modnum& operator *= (const modnum& o) { v = int(int64(v) * int64(o.v) % MOD); return *this; } modnum& operator /= (const modnum& o) { return *this *= o.inv(); } friend modnum operator ++ (modnum& a, int) { modnum r = a; ++a; return r; } friend modnum operator -- (modnum& a, int) { modnum r = a; --a; return r; } friend modnum operator + (const modnum& a, const modnum& b) { return modnum(a) += b; } friend modnum operator - (const modnum& a, const modnum& b) { return modnum(a) -= b; } friend modnum operator * (const modnum& a, const modnum& b) { return modnum(a) *= b; } friend modnum operator / (const modnum& a, const modnum& b) { return modnum(a) /= b; } friend modnum power(modnum a, int64 n) { modnum ret = 1; for (; n; n >>= 1) { if (n & 1) ret *= a; a *= a; } return ret; } }; using mint = modnum; int main() { int n, m; cin >> n >> m; vector dp(n + 1), pre(n + 1); // vector dp(n + 1), pre(n + 1); dp[0] = 1; for (int i = 0; i < n; ++i) pre[i + 1] = pre[i] + dp[i]; for (int step = 1; step <= m; ++step) { vector ndp(n + 1); // vector ndp(n + 1); ndp[0] = 1; for (int i = 1; i <= n; ++i) { ndp[i] = pre[i] / i; } swap(dp, ndp); for (int i = 0; i < n; ++i) pre[i + 1] = pre[i] + dp[i]; // trace(step, dp); } cout << dp[n] << '\n'; return 0; }