#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; using Int = long long; template ostream &operator<<(ostream &os, const pair &a) { return os << "(" << a.first << ", " << a.second << ")"; }; template ostream &operator<<(ostream &os, const vector &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; } template void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; } template bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; } template bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; } #define COLOR(s) ("\x1b[" s "m") // exp(as) // assume as[0] == 0 // exp(a0 + a1 X) = exp(a0) + exp(a0) a1 X // ZT1: T[2^(n-1)][n] // ZT: T[2^n][n+1] template vector setExp(int n, const vector &as, ZT1 zas, ZT zbs) { assert(static_cast(as.size()) == 1 << n); assert(as[0] == 0); zbs[0][0] = 1; for (int m = 0; m < n; ++m) { // ranked a[2^m, 2^(m+1)) for (int h = 0; h < 1 << m; ++h) { memset(zas[h], 0, (m + 1) * sizeof(T)); zas[h][__builtin_popcount(h)] = as[(1 << m) + h]; } // zeta for (int w = 1; w < 1 << m; w <<= 1) { for (int h0 = 0; h0 < 1 << m; h0 += w << 1) for (int h = h0; h < h0 + w; ++h) { for (int k = 0; k <= m; ++k) zas[h + w][k] += zas[h][k]; } } for (int h = 0; h < 1 << m; ++h) { // zeta zbs[h][m + 1] = 0; memcpy(zbs[(1 << m) + h], zbs[h], ((m + 1) + 1) * sizeof(T)); // product for (int k = 0; k <= m; ++k) for (int l = 0; l <= m - k; ++l) { zbs[(1 << m) + h][k + l + 1] += zbs[h][k] * zas[h][l]; } } } // moebius for (int w = 1; w < 1 << n; w <<= 1) { for (int h0 = 0; h0 < 1 << n; h0 += w << 1) for (int h = h0; h < h0 + w; ++h) { for (int k = 0; k <= n; ++k) zbs[h + w][k] -= zbs[h][k]; } } // unrank vector bs(1 << n); for (int h = 0; h < 1 << n; ++h) bs[h] = zbs[h][__builtin_popcount(h)]; return bs; } using U = unsigned long long; constexpr int MAX_N = 13; int N, M; vector A, B; U zas[1 << MAX_N][MAX_N + 1]; U zbs[1 << MAX_N][MAX_N + 1]; U sub[1 << MAX_N][MAX_N]; int main() { for (; ~scanf("%d%d", &N, &M); ) { A.resize(M); B.resize(M); for (int i = 0; i < M; ++i) { scanf("%d%d", &A[i], &B[i]); --A[i]; --B[i]; } vector adj(N, 0); for (int i = 0; i < M; ++i) { adj[A[i]] |= 1 << B[i]; adj[B[i]] |= 1 << A[i]; } vector cyc(1 << N, 0); for (int s = 0; s < N; ++s) { for (int p = 0; p < 1 << s; ++p) { fill(sub[p], sub[p] + (s + 1), 0); } sub[0][s] = 1; for (int p = 0; p < 1 << s; ++p) for (int u = 0; u <= s; ++u) if (sub[p][u]) { for (int v = 0; v < s; ++v) if ((adj[u] >> v & 1) && !(p & 1 << v)) { sub[p | 1 << v][v] += sub[p][u]; } if (p != 1 << u && (adj[u] >> s & 1)) { cyc[p | 1 << s] += sub[p][u]; } } cyc[1 << s] = 1; for (int p = 1; p < 1 << s; ++p) if (cyc[p | 1 << s]) { assert(__builtin_popcount(p) >= 2); assert(cyc[p | 1 << s] % 2 == 0); cyc[p | 1 << s] /= 2; } } // cerr<<"cyc = "< tree(1 << N, 0); for (int s = 0; s < N; ++s) { for (int p = 1 << s; p < 1 << (s + 1); ++p) if (cyc[p]) { vector us; for (int u = 0; u < s; ++u) if (!(p & 1 << u)) { us.push_back(u); } const int usLen = us.size(); vector qs(1 << usLen, 0); vector ways(1 << usLen, 0); for (int x = 0; x < usLen; ++x) { const int deg = __builtin_popcount(adj[us[x]] & p); for (int h = 0; h < 1 << x; ++h) { qs[h | 1 << x] = qs[h] | 1 << us[x]; ways[h | 1 << x] = ways[h] + deg; } } vector fs(1 << usLen, 0); for (int h = 0; h < 1 << usLen; ++h) { fs[h] = ways[h] * tree[qs[h]]; } const auto gs = setExp(usLen, fs, zas, zbs); // cerr<