#include using namespace std; using pint = pair; struct fast_ios { fast_ios(){ cin.tie(nullptr), ios::sync_with_stdio(false), cout << fixed << setprecision(20); }; } fast_ios_; #define ALL(x) (x).begin(), (x).end() #define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i=i##_begin_;i--) #define REP(i, n) FOR(i,0,n) #define IREP(i, n) IFOR(i,0,n) template vector sort_unique(vector vec) { sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end()); return vec; } template struct ModInt { #if __cplusplus >= 201402L #define MDCONST constexpr #else #define MDCONST #endif using lint = long long; static int get_mod() { return mod; } static int get_primitive_root() { static int primitive_root = 0; if (!primitive_root) { primitive_root = [&]() { std::set fac; int v = mod - 1; for (lint i = 2; i * i <= v; i++) while (v % i == 0) fac.insert(i), v /= i; if (v > 1) fac.insert(v); for (int g = 1; g < mod; g++) { bool ok = true; for (auto i : fac) if (ModInt(g).power((mod - 1) / i) == 1) { ok = false; break; } if (ok) return g; } return -1; }(); } return primitive_root; } int val; MDCONST ModInt() : val(0) {} MDCONST ModInt &_setval(lint v) { val = (v >= mod ? v - mod : v); return *this; } MDCONST ModInt(lint v) { _setval(v % mod + mod); } explicit operator bool() const { return val != 0; } MDCONST ModInt operator+(const ModInt &x) const { return ModInt()._setval((lint)val + x.val); } MDCONST ModInt operator-(const ModInt &x) const { return ModInt()._setval((lint)val - x.val + mod); } MDCONST ModInt operator*(const ModInt &x) const { return ModInt()._setval((lint)val * x.val % mod); } MDCONST ModInt operator/(const ModInt &x) const { return ModInt()._setval((lint)val * x.inv() % mod); } MDCONST ModInt operator-() const { return ModInt()._setval(mod - val); } MDCONST ModInt &operator+=(const ModInt &x) { return *this = *this + x; } MDCONST ModInt &operator-=(const ModInt &x) { return *this = *this - x; } MDCONST ModInt &operator*=(const ModInt &x) { return *this = *this * x; } MDCONST ModInt &operator/=(const ModInt &x) { return *this = *this / x; } friend MDCONST ModInt operator+(lint a, const ModInt &x) { return ModInt()._setval(a % mod + x.val); } friend MDCONST ModInt operator-(lint a, const ModInt &x) { return ModInt()._setval(a % mod - x.val + mod); } friend MDCONST ModInt operator*(lint a, const ModInt &x) { return ModInt()._setval(a % mod * x.val % mod); } friend MDCONST ModInt operator/(lint a, const ModInt &x) { return ModInt()._setval(a % mod * x.inv() % mod); } MDCONST bool operator==(const ModInt &x) const { return val == x.val; } MDCONST bool operator!=(const ModInt &x) const { return val != x.val; } MDCONST bool operator<(const ModInt &x) const { return val < x.val; } // To use std::map friend std::istream &operator>>(std::istream &is, ModInt &x) { lint t; return is >> t, x = ModInt(t), is; } MDCONST friend std::ostream &operator<<(std::ostream &os, const ModInt &x) { return os << x.val; } MDCONST lint power(lint n) const { lint ans = 1, tmp = this->val; while (n) { if (n & 1) ans = ans * tmp % mod; tmp = tmp * tmp % mod, n /= 2; } return ans; } MDCONST ModInt pow(lint n) const { return power(n); } MDCONST lint inv() const { return this->power(mod - 2); } ModInt fac() const { static std::vector facs; int l0 = facs.size(); if (l0 > this->val) return facs[this->val]; facs.resize(this->val + 1); for (int i = l0; i <= this->val; i++) facs[i] = (i == 0 ? ModInt(1) : facs[i - 1] * ModInt(i)); return facs[this->val]; } ModInt doublefac() const { lint k = (this->val + 1) / 2; return (this->val & 1) ? ModInt(k * 2).fac() / (ModInt(2).pow(k) * ModInt(k).fac()) : ModInt(k).fac() * ModInt(2).pow(k); } ModInt nCr(const ModInt &r) const { return (this->val < r.val) ? 0 : this->fac() / ((*this - r).fac() * r.fac()); } ModInt sqrt() const { if (val == 0) return 0; if (mod == 2) return val; if (power((mod - 1) / 2) != 1) return 0; ModInt b = 1; while (b.power((mod - 1) / 2) == 1) b += 1; int e = 0, m = mod - 1; while (m % 2 == 0) m >>= 1, e++; ModInt x = power((m - 1) / 2), y = (*this) * x * x; x *= (*this); ModInt z = b.power(m); while (y != 1) { int j = 0; ModInt t = y; while (t != 1) j++, t *= t; z = z.power(1LL << (e - j - 1)); x *= z, z *= z, y *= z; e = j; } return ModInt(std::min(x.val, mod - x.val)); } }; using mint = ModInt<998244353>; template struct matrix { int H, W; std::vector elem; typename std::vector::iterator operator[](int i) { return elem.begin() + i * W; } inline T &at(int i, int j) { return elem[i * W + j]; } inline T get(int i, int j) const { return elem[i * W + j]; } operator std::vector>() const { std::vector> ret(H); for (int i = 0; i < H; i++) std::copy(elem.begin() + i * W, elem.begin() + (i + 1) * W, std::back_inserter(ret[i])); return ret; } matrix() = default; matrix(int H, int W) : H(H), W(W), elem(H * W) {} matrix(const std::vector> &d) : H(d.size()), W(d.size() ? d[0].size() : 0) { for (auto &raw : d) std::copy(raw.begin(), raw.end(), std::back_inserter(elem)); } static matrix Identity(int N) { matrix ret(N, N); for (int i = 0; i < N; i++) ret.at(i, i) = 1; return ret; } matrix operator-() const { matrix ret(H, W); for (int i = 0; i < H * W; i++) ret.elem[i] = -elem[i]; return ret; } matrix operator*(const T &v) const { matrix ret = *this; for (auto &x : ret.elem) x *= v; return ret; } matrix operator/(const T &v) const { matrix ret = *this; for (auto &x : ret.elem) x /= v; return ret; } matrix operator+(const matrix &r) const { matrix ret = *this; for (int i = 0; i < H * W; i++) ret.elem[i] += r.elem[i]; return ret; } matrix operator-(const matrix &r) const { matrix ret = *this; for (int i = 0; i < H * W; i++) ret.elem[i] -= r.elem[i]; return ret; } matrix operator*(const matrix &r) const { matrix ret(H, r.W); for (int i = 0; i < H; i++) { for (int k = 0; k < W; k++) { for (int j = 0; j < r.W; j++) { ret.at(i, j) += this->get(i, k) * r.get(k, j); } } } return ret; } matrix &operator*=(const T &v) { return *this = *this * v; } matrix &operator/=(const T &v) { return *this = *this / v; } matrix &operator+=(const matrix &r) { return *this = *this + r; } matrix &operator-=(const matrix &r) { return *this = *this - r; } matrix &operator*=(const matrix &r) { return *this = *this * r; } bool operator==(const matrix &r) const { return H == r.H and W == r.W and elem == r.elem; } bool operator!=(const matrix &r) const { return H != r.H or W != r.W or elem != r.elem; } bool operator<(const matrix &r) const { return elem < r.elem; } matrix pow(int64_t n) const { matrix ret = Identity(H); if (n == 0) return ret; for (int i = 63 - __builtin_clzll(n); i >= 0; i--) { ret *= ret; if ((n >> i) & 1) ret *= (*this); } return ret; } matrix transpose() const { matrix ret(W, H); for (int i = 0; i < H; i++) for (int j = 0; j < W; j++) ret.at(j, i) = this->get(i, j); return ret; } // Gauss-Jordan elimination // - Require inverse for every non-zero element // - Complexity: O(H^2 W) matrix gauss_jordan() const { int c = 0; matrix mtr(*this); for (int h = 0; h < H; h++) { if (c == W) break; int piv = -1; for (int j = h; j < H; j++) if (mtr.get(j, c)) { piv = j; break; } if (piv == -1) { c++; h--; continue; } if (h != piv) { for (int w = 0; w < W; w++) { std::swap(mtr[piv][w], mtr[h][w]); mtr.at(piv, w) *= -1; // To preserve sign of determinant } } for (int hh = 0; hh < H; hh++) if (hh != h) { T coeff = mtr.at(hh, c) * mtr.at(h, c).inv(); for (int w = W - 1; w >= c; w--) { mtr.at(hh, w) -= mtr.at(h, w) * coeff; } } c++; } return mtr; } int rank_of_gauss_jordan() const { for (int i = H * W - 1; i >= 0; i--) if (elem[i]) return i / W + 1; return 0; } T determinant_of_upper_triangle() const { T ret = 1; for (int i = 0; i < H; i++) ret *= get(i, i); return ret; } int inverse() { assert(H == W); std::vector> ret = Identity(H), tmp = *this; int rank = 0; for (int i = 0; i < H; i++) { int ti = i; while (ti < H and tmp[ti][i] == 0) ti++; if (ti == H) continue; else rank++; ret[i].swap(ret[ti]), tmp[i].swap(tmp[ti]); T inv = tmp[i][i].inv(); for (int j = 0; j < W; j++) { ret[i][j] *= inv; } for (int j = i + 1; j < W; j++) { tmp[i][j] *= inv; } for (int h = 0; h < H; h++) { if (i == h) continue; const T c = -tmp[h][i]; for (int j = 0; j < W; j++) { ret[h][j] += ret[i][j] * c; } for (int j = i + 1; j < W; j++) { tmp[h][j] += tmp[i][j] * c; } } } *this = ret; return rank; } friend std::vector operator*(const matrix &m, const std::vector &v) { assert(m.W == int(v.size())); std::vector ret(m.H); for (int i = 0; i < m.H; i++) { for (int j = 0; j < m.W; j++) { ret[i] += m.get(i, j) * v[j]; } } return ret; } friend std::vector operator*(const std::vector &v, const matrix &m) { assert(int(v.size()) == m.H); std::vector ret(m.W); for (int i = 0; i < m.H; i++) { for (int j = 0; j < m.W; j++) { ret[j] += v[i] * m.get(i, j); } } return ret; } friend std::ostream &operator<<(std::ostream &os, const matrix &x) { os << "[(" << x.H << " * " << x.W << " matrix)"; os << "\n[column sums: "; for (int j = 0; j < x.W; j++) { T s = 0; for (int i = 0; i < x.H; i++) s += x.get(i, j); os << s << ","; } os << "]"; for (int i = 0; i < x.H; i++) { os << "\n["; for (int j = 0; j < x.W; j++) os << x.get(i, j) << ","; os << "]"; } os << "]\n"; return os; } friend std::istream &operator>>(std::istream &is, matrix &x) { for (auto &v : x.elem) is >> v; return is; } }; // UnionFind Tree (0-indexed), based on size of each disjoint set struct UnionFind { std::vector par, cou; UnionFind(int N = 0) : par(N), cou(N, 1) { iota(par.begin(), par.end(), 0); } int find(int x) { return (par[x] == x) ? x : (par[x] = find(par[x])); } bool unite(int x, int y) { x = find(x), y = find(y); if (x == y) return false; if (cou[x] < cou[y]) std::swap(x, y); par[y] = x, cou[x] += cou[y]; return true; } int count(int x) { return cou[find(x)]; } bool same(int x, int y) { return find(x) == find(y); } }; mint gyoretsuki(const vector &vs, const vector &edges) { int D = vs.size(); matrix mat(D - 1, D - 1); for (auto [u, v] : edges) { const int i = lower_bound(ALL(vs), u) - vs.begin(); const int j = lower_bound(ALL(vs), v) - vs.begin(); if (i < D - 1) mat[i][i] += 1; if (j < D - 1) mat[j][j] += 1; if (i + 1 < D and j + 1 < D) { mat[i][j] -= 1, mat[j][i] -= 1; } } mat = mat.gauss_jordan(); return mat.determinant_of_upper_triangle(); } mint solve1(const int N, const vector &edges) { if (N <= 1) return 1; vector d0(N, vector(N)); vector d1(N, vector(N)); for (auto [u, v] : edges) { d0[u][u] += 1; d0[v][v] += 1; d0[v][u] -= 1; d0[u][v] -= 1; } REP(i, N) REP(j, i) if (d0[i][j] == 0) { d1[i][j] -= 1; d1[j][i] -= 1; d1[i][i] += 1; d1[j][j] += 1; } d0.resize(N - 1); d1.resize(N - 1); mint r0 = 1, r1 = 0; REP(i, N - 1) d0[i].resize(N - 1), d1[i].resize(N - 1); REP(i, N - 1) { mint p = d0[i][i].inv(), q = -d1[i][i] * p * p; mint r0new = r0 * d0[i][i]; mint r1new = r1 * d0[i][i] + r0 * d1[i][i]; FOR(j, i, N - 1) { d1[i][j] = d1[i][j] * p + d0[i][j] * q; d0[i][j] = d0[i][j] * p; } FOR(l, i + 1, N - 1) { IFOR(j, i, N - 1) { d1[l][j] -= d1[l][i] * d0[i][j] + d0[l][i] * d1[i][j]; d0[l][j] -= d0[l][i] * d0[i][j]; } } r0 = r0new, r1 = r1new; } return r0 + r1; } int main() { int N, M; cin >> N >> M; vector edges; UnionFind uf1(N); REP(e, M) { int u, v; cin >> u >> v; u--, v--; edges.emplace_back(u, v); uf1.unite(u, v); } if (uf1.count(0) == N) { cout << "0\n" << solve1(N, edges) << '\n'; return 0; } int maxi = 0, cntmaxi = 0; int fuben = 0; REP(i, N) REP(j, N) fuben += !uf1.same(i, j); REP(i, N) REP(j, i) if (!uf1.same(i, j)) { int s = uf1.count(i) * uf1.count(j); if (s > maxi) maxi = s, cntmaxi = 1; else if (maxi == s) cntmaxi++; } mint ret = cntmaxi; vector> r2is(N); vector> r2edges(N); REP(i, N) r2is[uf1.find(i)].emplace_back(i); for (auto [u, v] : edges) r2edges[uf1.find(u)].emplace_back(u, v); REP(r, N) if (r2is[r].size()) ret *= gyoretsuki(r2is[r], r2edges[r]); cout << fuben - maxi * 2 << '\n' << ret << '\n'; }