/* Problem URL: https://codeforces.com/gym/105327/problem/B */ #include #include #include using namespace std; using namespace __gnu_pbds; template > using ordered_set = tree; #define V vector #define rmin(a, b) a = min(a, b) #define rmax(a, b) a = max(a, b) #define rep(i, lim) for (int i = 0; i < (lim); i++) #define nrep(i, s, lim) for (int i = s; i < (lim); i++) #define repv(i, v) for (auto &i : (v)) #define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; } #define sortv(v) sort(v.begin(), v.end()) #define all(v) (v).begin(), (v).end() using vi = vector; using vvi = vector; using vvvi = vector; using vvvvi = vector; using ll = long long; using vl = vector; using vvl = vector; using vvvl = vector; using vvvvl = vector; template auto operator<<(ostream &os, const vector &vec)->ostream& { os << vec[0]; for (size_t i = 1; i < vec.size(); i++) { os << ' ' << vec[i]; } os << '\n'; return os; } template auto operator>>(istream &is, vector &vec)->istream& { for (auto &i : vec) { is >> i; } return is; } template auto operator<<(ostream &os, const vector> &vec)->ostream& { for (auto &i : vec) { os << i[0]; for (size_t j = 1; j < i.size(); j++) { os << ' ' << i[j]; } os << '\n'; } return os; } template auto operator>>(istream &is, vector> &vec)->istream& { for (auto &i : vec) { for (auto &j : i) { is >> j; } } return is; } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n, m; cin >> n >> m; vvi tree(n + m); vi dsu(n + m); rep(i, dsu.size()) { dsu[i] = i; } function find_p = [&](int i) { if (dsu[i] == i) { return i; } return dsu[i] = find_p(dsu[i]); }; auto join = [&](int a, int b) { a = find_p(a); b = find_p(b); if (a == b) { return false; } dsu[a] = b; return true; }; rep(i, n) { int k; cin >> k; while (k--) { int j; cin >> j; j--; if (!join(i, j + n)) { continue; } tree[i].push_back(j + n); tree[j + n].push_back(i); } } vvi parent(n + m, vi(25)); vi depth(n + m, -1); vi group(n + m, -1); int g = 0; V vis(n + m); function buildlca = [&](int i, int p) { parent[i][0] = p; depth[i] = depth[p] + 1; group[i] = g; vis[i] = true; nrep(j, 1, 25) { parent[i][j] = parent[parent[i][j - 1]][j - 1]; } for (auto j : tree[i]) { if (j == p) { continue; } buildlca(j, i); } }; rep(i, n + m) { if (vis[i]) { continue; } buildlca(i, i); g++; } auto lca = [&](int a, int b) { if (depth[a] > depth[b]) { swap(a, b); } int diff = depth[b] - depth[a]; rep(i, 25) { if ((diff >> i) & 1) { b = parent[b][i]; } } if (a == b) { return a; } for (int i = 24; i >= 0; i--) { if (parent[a][i] == parent[b][i]) { continue; } a = parent[a][i]; b = parent[b][i]; } return parent[a][0]; }; int q; cin >> q; while (q--) { int a, b; cin >> a >> b; a--, b--; a += n; b += n; if (group[a] != group[b]) { cout << "-1\n"; continue; } int p = lca(a, b); vi ans1; vi ans2; while (a != p) { ans1.push_back(a + 1); a = parent[a][0]; } ans1.push_back(a + 1); while (b != p) { ans2.push_back(b + 1); b = parent[b][0]; } reverse(all(ans2)); cout << (ans1.size() + ans2.size() + 1) / 2 << '\n'; repv(i, ans1) { cout << i - (i > n ? n : 0) << ' '; } repv(i, ans2) { cout << i - (i > n ? n : 0) << ' '; } cout << '\n'; } }