#pragma region preprocessor #ifdef LOCAL //* #define _GLIBCXX_DEBUG // gcc /*/ #define _LIBCPP_DEBUG 0 // clang //*/ // #define __buffer_check__ #else #pragma GCC optimize("Ofast") // #define NDEBUG #endif #define __precision__ 15 #define __iostream_untie__ true #include #include #ifdef LOCAL #include "dump.hpp" #define mesg(str) std::cerr << "[ " << __LINE__ << " : " << __FUNCTION__ << " ] " << str << "\n" #else #define dump(...) ((void)0) #define mesg(str) ((void)0) #endif #pragma endregion #pragma region std-overload namespace std { // hash template size_t hash_combine(size_t seed, T const &key) { return seed ^ (hash()(key) + 0x9e3779b9 + (seed << 6) + (seed >> 2)); } template struct hash> { size_t operator()(pair const &pr) const { return hash_combine(hash_combine(0, pr.first), pr.second); } }; template ::value - 1> struct tuple_hash_calc { static size_t apply(size_t seed, tuple_t const &t) { return hash_combine(tuple_hash_calc::apply(seed, t), get(t)); } }; template struct tuple_hash_calc { static size_t apply(size_t seed, tuple_t const &t) { return hash_combine(seed, get<0>(t)); } }; template struct hash> { size_t operator()(tuple const &t) const { return tuple_hash_calc>::apply(0, t); } }; // iostream template istream &operator>>(istream &is, pair &p) { return is >> p.first >> p.second; } template ostream &operator<<(ostream &os, const pair &p) { return os << p.first << ' ' << p.second; } template struct tupleis { static istream &apply(istream &is, tuple_t &t) { tupleis::apply(is, t); return is >> get(t); } }; template struct tupleis { static istream &apply(istream &is, tuple_t &t) { return is; } }; template istream &operator>>(istream &is, tuple &t) { return tupleis, tuple_size>::value - 1>::apply(is, t); } template <> istream &operator>>(istream &is, tuple<> &t) { return is; } template struct tupleos { static ostream &apply(ostream &os, const tuple_t &t) { tupleos::apply(os, t); return os << ' ' << get(t); } }; template struct tupleos { static ostream &apply(ostream &os, const tuple_t &t) { return os << get<0>(t); } }; template ostream &operator<<(ostream &os, const tuple &t) { return tupleos, tuple_size>::value - 1>::apply(os, t); } template <> ostream &operator<<(ostream &os, const tuple<> &t) { return os; } template , string>::value, nullptr_t> = nullptr> istream& operator>>(istream& is, Container &cont) { for(auto&& e : cont) is >> e; return is; } template , string>::value, nullptr_t> = nullptr> ostream& operator<<(ostream& os, const Container &cont) { bool flag = 1; for(auto&& e : cont) flag ? flag = 0 : (os << ' ', 0), os << e; return os; } } // namespace std #pragma endregion #pragma region config namespace config { const auto start_time{std::chrono::system_clock::now()}; int64_t elapsed() { using namespace std::chrono; const auto end_time{std::chrono::system_clock::now()}; return duration_cast(end_time - start_time).count(); } __attribute__((constructor)) void setup() { using namespace std; if(__iostream_untie__) ios::sync_with_stdio(false), cin.tie(nullptr); cout << fixed << setprecision(__precision__); #ifdef DEBUG freopen("debug.out","w",stdout); freopen("debug.err","w",stderr); if(!freopen("debug.in","r",stdin)) { cerr << "error: \"./debug.in\" not found.\n"; exit(EXIT_FAILURE); } #endif #ifdef stderr_path freopen(stderr_path, "a", stderr); #endif #ifdef LOCAL cerr << fixed << setprecision(__precision__) << boolalpha << "\n----- stderr at LOCAL -----\n\n"; atexit([]{ cerr << "\n----- Exec time : " << elapsed() << " ms -----\n\n"; }); #endif #ifdef __buffer_check__ atexit([]{ ofstream cnsl("CON"); char bufc; if(cin >> bufc) cnsl << "\n\033[1;35mwarning\033[0m: buffer not empty.\n\n"; }); #endif } } // namespace config #pragma endregion #pragma region utility // lambda wrapper for recursive method. template class fixed_point { lambda_type func; public: fixed_point(lambda_type &&f) : func(std::move(f)) {} template auto operator()(Args &&... args) const { return func(*this, std::forward(args)...); } }; // read with std::cin. template struct read { typename std::remove_const::type value; template read(types... args) : value(args...) { std::cin >> value; } operator T() const { return value; } }; template <> struct read { template operator T() const { T value; std::cin >> value; return value; } }; // substitute y for x if x > y. template inline bool chmin(T &x, const T &y) { return x > y ? x = y, true : false; } // substitute y for x if x < y. template inline bool chmax(T &x, const T &y) { return x < y ? x = y, true : false; } // binary search on discrete range. template iter_type binary(iter_type __ok, iter_type __ng, pred_type pred) { assert(__ok != __ng); std::ptrdiff_t dist(__ng - __ok); while(std::abs(dist) > 1) { iter_type mid(__ok + dist / 2); if(pred(mid)) __ok = mid, dist -= dist / 2; else __ng = mid, dist /= 2; } return __ok; } // binary search on real numbers. template long double binary(long double __ok, long double __ng, const long double eps, pred_type pred) { assert(__ok != __ng); while(std::abs(__ok - __ng) > eps) { long double mid{(__ok + __ng) / 2}; (pred(mid) ? __ok : __ng) = mid; } return __ok; } // trinary search on discrete range. template iter_type trinary(iter_type __first, iter_type __last, comp_type comp) { assert(__first < __last); std::ptrdiff_t dist(__last - __first); while(dist > 2) { iter_type __left(__first + dist / 3), __right(__first + dist * 2 / 3); if(comp(__left, __right)) __last = __right, dist = dist * 2 / 3; else __first = __left, dist -= dist / 3; } if(dist > 1 && comp(next(__first), __first)) ++__first; return __first; } // trinary search on real numbers. template long double trinary(long double __first, long double __last, const long double eps, comp_type comp) { assert(__first < __last); while(__last - __first > eps) { long double __left{(__first * 2 + __last) / 3}, __right{(__first + __last * 2) / 3}; if(comp(__left, __right)) __last = __right; else __first = __left; } return __first; } // size of array. template size_t size(A (&array)[N]) { return N; } // be careful that val is type-sensitive. template void init(A (&array)[N], const T &val) { std::fill((T*)array, (T*)(array + N), val); } #pragma endregion #pragma region alias using namespace std; using i32 = int_least32_t; using i64 = int_least64_t; using u32 = uint_least32_t; using u64 = uint_least64_t; using p32 = pair; using p64 = pair; template > using heap = priority_queue, Comp>; template using hashset = unordered_set; template using hashmap = unordered_map; using namespace __gnu_cxx; #pragma endregion #pragma region library // verified at https://judge.yosupo.jp/submission/3400 #ifndef union_find_hpp #define union_find_hpp #include #include class union_find { std::vector link; public: explicit union_find(const unsigned n = 0) : link(n, -1) {} unsigned find(unsigned x) { assert(x < size()); return link[x] < 0 ? x : (link[x] = find(link[x])); } unsigned size() const { return link.size(); } unsigned size(const unsigned x) { assert(x < size()); return -link[find(x)]; } bool same(const unsigned x, const unsigned y) { assert(x < size() && y < size()); return find(x) == find(y); } bool unite(unsigned x, unsigned y) { assert(x < size() && y < size()); x = find(x), y = find(y); if(x == y) return false; if(link[x] > link[y]) std::swap(x, y); link[x] += link[y]; link[y] = x; return true; } }; // class union_find #endif // union_find_hpp #ifndef number_theoretic_transform_hpp #define number_theoretic_transform_hpp #include #include #include #include namespace number_theoretic_transform { constexpr int mod = 998244353; constexpr int primitive = 3; class modint { int val; public: constexpr modint() noexcept : val{0} {} constexpr modint(long long x) noexcept : val((x %= mod) < 0 ? mod + x : x) {} constexpr long long value() const noexcept { return val; } constexpr modint operator++(int) noexcept { modint t = *this; return ++val, t; } constexpr modint operator--(int) noexcept { modint t = *this; return --val, t; } constexpr modint &operator++() noexcept { return ++val, *this; } constexpr modint &operator--() noexcept { return --val, *this; } constexpr modint operator-() const noexcept { return modint(-val); } constexpr modint &operator+=(const modint &other) noexcept { return (val += other.val) < mod ? 0 : val -= mod, *this; } constexpr modint &operator-=(const modint &other) noexcept { return (val += mod - other.val) < mod ? 0 : val -= mod, *this; } constexpr modint &operator*=(const modint &other) noexcept { return val = (long long)val * other.val % mod, *this; } constexpr modint &operator/=(const modint &other) noexcept { return *this *= inverse(other); } constexpr modint operator+(const modint &other) const noexcept { return modint(*this) += other; } constexpr modint operator-(const modint &other) const noexcept { return modint(*this) -= other; } constexpr modint operator*(const modint &other) const noexcept { return modint(*this) *= other; } constexpr modint operator/(const modint &other) const noexcept { return modint(*this) /= other; } constexpr bool operator==(const modint &other) const noexcept { return val == other.val; } constexpr bool operator!=(const modint &other) const noexcept { return val != other.val; } constexpr bool operator!() const noexcept { return !val; } friend constexpr modint operator+(long long x, modint y) noexcept { return modint(x) + y; } friend constexpr modint operator-(long long x, modint y) noexcept { return modint(x) - y; } friend constexpr modint operator*(long long x, modint y) noexcept { return modint(x) * y; } friend constexpr modint operator/(long long x, modint y) noexcept { return modint(x) / y; } static constexpr modint inverse(const modint &other) noexcept { assert(other != 0); int a{mod}, b{other.val}, u{}, v{1}, t{}; while(b) t = a / b, a ^= b ^= (a -= t * b) ^= b, u ^= v ^= (u -= t * v) ^= v; return {u}; } static constexpr modint pow(modint other, long long e) noexcept { if(e < 0) e = e % (mod - 1) + mod - 1; modint res{1}; while(e) { if(e & 1) res *= other; other *= other, e >>= 1; } return res; } friend std::ostream &operator<<(std::ostream &os, const modint &other) noexcept { return os << other.val; } friend std::istream &operator>>(std::istream &is, modint &other) noexcept { long long val; other = {(is >> val, val)}; return is; } }; // class modint class zeta_calc { static constexpr size_t n = __builtin_ctz(mod - 1); modint _zeta[n + 1]; public: constexpr zeta_calc() : _zeta{} { _zeta[n] = modint::pow(modint(primitive), (mod - 1) / (1 << n)); for(size_t i{n}; i; --i) _zeta[i - 1] = _zeta[i] * _zeta[i]; } constexpr modint operator[](size_t k) const { return _zeta[k]; } }; // class zeta_calc constexpr zeta_calc zeta; class inv_calc { static constexpr size_t n = __builtin_ctz(mod - 1); modint _inv[n + 1]; public: constexpr inv_calc() : _inv{1, (mod + 1) / 2} { for(size_t i{1}; i < n; ++i) _inv[i + 1] = _inv[i] * _inv[1]; } constexpr modint operator[](size_t k) const { return _inv[k]; } }; // class inv_calc constexpr inv_calc inv; using poly_t = std::vector; void discrete_Fourier_transform(poly_t &f) { const size_t n{f.size()}, mask{n - 1}; assert(__builtin_popcount(n) == 1); // degree of f must be a power of two. static poly_t g; g.resize(n); for(size_t i{n >> 1}, ii{1}; i; i >>= 1, ++ii, swap(f, g)) { modint powzeta{1}; for(size_t j{}; j < n; powzeta *= zeta[ii]) { for(size_t k{}, x{mask & j << 1}, y{mask & (i + (j << 1))}; k < i; ++k, ++j, ++x, ++y) { g[j] = f[x] + powzeta * f[y]; } } } } void inverse_discrete_Fourier_transform(poly_t &f) { discrete_Fourier_transform(f), reverse(next(f.begin()), f.end()); const size_t k = __builtin_ctz(f.size()); for(modint &e : f) e *= inv[k]; } poly_t convolute(poly_t f, poly_t g) { if(f.empty() || g.empty()) return poly_t(); const size_t deg_f{f.size() - 1}, deg_g{g.size() - 1}, deg_h{deg_f + deg_g}, n(1u << (32 - __builtin_clz(deg_h))); static poly_t h; f.resize(n, 0), g.resize(n, 0), h.resize(n); discrete_Fourier_transform(f), discrete_Fourier_transform(g); for(size_t i{}; i < n; ++i) h[i] = f[i] * g[i]; inverse_discrete_Fourier_transform(h); h.resize(deg_h + 1); return h; } } // namespace Number_theoretic_transform #endif // number_theoretic_transform_hpp #pragma endregion struct solver; template void main_(); int main() { main_(); } template void main_() { unsigned t = 1; #ifdef LOCAL t = 1; #endif // t = -1; // infinite loop // cin >> t; // case number given while(t--) solver(); } struct solver { solver() { using namespace number_theoretic_transform; using mint=modint; int n,m; cin>>n>>m; vector ed(m); cin>>ed; int spv=0; { vector sv; for(auto [a,b]: ed) { sv.emplace_back(a); sv.emplace_back(b); } sort(begin(sv), end(sv)); sv.erase(unique(begin(sv), end(sv)), end(sv)); for(auto &[a,b]: ed) { a=lower_bound(begin(sv), end(sv), a)-begin(sv); b=lower_bound(begin(sv), end(sv), b)-begin(sv); } spv=sv.size(); } mint ans=0; { mint y=1; for(int x=n,u=1; x>0; u++,x--) { y*=x; if(u>=3) ans+=y/u; } } ans/=2; poly_t pex(n+1); pex[0]=1; for(int i=1; i<=n; i++) { pex[i]=pex[i-1]/i; } vector q(m+1); for(int c=0; c<=m; c++) { q[c].resize(n+1); q[c][0]=1; for(int i=1; i<=c; i++) q[c][0]*=i; for(int i=1; i<=n; i++) { q[c][i]=q[c][i-1]/i*(i+c); } q[c]=convolute(q[c],pex); mint fa=1; for(int i=1; i<=n; i++) { fa*=i; q[c][i]*=fa; } } for(int s=1; s<1< cnt(spv); bool fail=0; int con=0; int sz=0; bool cycl=false; int cmp=spv; for(int i=0; i>i&1) { sz++; auto [a,b]=ed[i]; if(!uf.unite(a,b)) cycl=1; else cmp--; if(cnt[a]>1 || cnt[b]>1) fail=1; cnt[a]++; cnt[b]++; } } if(cycl) { int no=0; for(int x: cnt) no+=x>0; if(cmp>spv-no+1) fail=1; } if(fail) continue; for(int x: cnt) if(x>1) con++; if(sz>con) { mint tmp=q[sz-con-1][n-sz*2+con]; if(sz==1) { tmp-=1; } for(int x=1; x