#line 1 "main.cpp" #include //#pragma GCC target("avx,avx2") //#pragma GCC optimize("O3") //#pragma GCC optimize("unroll-loops") #ifdef LOCAL #include #define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__) #else #define debug(...) (static_cast(0)) #endif using namespace std; using ll = long long; using ull = unsigned long long; using ld = long double; using pll = pair; using pii = pair; using vi = vector; using vvi = vector; using vvvi = vector; using vl = vector; using vvl = vector; using vvvl = vector; using vul = vector; using vpii = vector; using vvpii = vector; using vpll = vector; using vs = vector; template using pq = priority_queue, greater>; #define overload4(_1, _2, _3, _4, name, ...) name #define overload3(a,b,c,name,...) name #define rep1(n) for (ll UNUSED_NUMBER = 0; UNUSED_NUMBER < (n); ++UNUSED_NUMBER) #define rep2(i, n) for (ll i = 0; i < (n); ++i) #define rep3(i, a, b) for (ll i = (a); i < (b); ++i) #define rep4(i, a, b, c) for (ll i = (a); i < (b); i += (c)) #define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__) #define rrep1(n) for(ll i = (n) - 1;i >= 0;i--) #define rrep2(i,n) for(ll i = (n) - 1;i >= 0;i--) #define rrep3(i,a,b) for(ll i = (b) - 1;i >= (a);i--) #define rrep4(i,a,b,c) for(ll i = (a) + ((b)-(a)-1) / (c) * (c);i >= (a);i -= c) #define rrep(...) overload4(__VA_ARGS__, rrep4, rrep3, rrep2, rrep1)(__VA_ARGS__) #define all1(i) begin(i) , end(i) #define all2(i,a) begin(i) , begin(i) + a #define all3(i,a,b) begin(i) + a , begin(i) + b #define all(...) overload3(__VA_ARGS__, all3, all2, all1)(__VA_ARGS__) #define sum(...) accumulate(all(__VA_ARGS__),0LL) template bool chmin(T &a, const T &b){ if(a > b){ a = b; return 1; } else return 0; } template bool chmax(T &a, const T &b){ if(a < b){ a = b; return 1; } else return 0; } template auto min(const T& a){return *min_element(all(a));} template auto max(const T& a){return *max_element(all(a));} template void in(Ts&... t); #define INT(...) int __VA_ARGS__; in(__VA_ARGS__) #define LL(...) ll __VA_ARGS__; in(__VA_ARGS__) #define STR(...) string __VA_ARGS__; in(__VA_ARGS__) #define CHR(...) char __VA_ARGS__; in(__VA_ARGS__) #define DBL(...) double __VA_ARGS__; in(__VA_ARGS__) #define LD(...) ld __VA_ARGS__; in(__VA_ARGS__) #define VEC(type, name, size) vector name(size); in(name) #define VV(type, name, h, w) vector> name(h, vector(w)); in(name) ll intpow(ll a, ll b){ ll ans = 1; while(b){if(b & 1) ans *= a; a *= a; b /= 2;} return ans;} ll modpow(ll a, ll b, ll p){ ll ans = 1; a %= p;if(a < 0) a += p;while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; } bool is_clamp(ll val,ll low,ll high) {return low <= val && val < high;} void Yes() {cout << "Yes\n";return;} void No() {cout << "No\n";return;} void YES() {cout << "YES\n";return;} void NO() {cout << "NO\n";return;} template T floor(T a, T b) {return a / b - (a % b && (a ^ b) < 0);} template T ceil(T x, T y) {return floor(x + y - 1, y);} template T bmod(T x, T y) {return x - y * floor(x, y);} template pair divmod(T x, T y) {T q = floor(x, y);return {q, x - q * y};} namespace IO{ #define VOID(a) decltype(void(a)) struct setting{ setting(){cin.tie(nullptr); ios::sync_with_stdio(false);fixed(cout); cout.precision(12);}} setting; template struct P : P{}; template<> struct P<0>{}; template void i(T& t){ i(t, P<3>{}); } void i(vector::reference t, P<3>){ int a; i(a); t = a; } template auto i(T& t, P<2>) -> VOID(cin >> t){ cin >> t; } template auto i(T& t, P<1>) -> VOID(begin(t)){ for(auto&& x : t) i(x); } template void ituple(T& t, index_sequence){in(get(t)...);} template auto i(T& t, P<0>) -> VOID(tuple_size{}){ituple(t, make_index_sequence::value>{});} #undef VOID } #define unpack(a) (void)initializer_list{(a, 0)...} template void in(Ts&... t){ unpack(IO :: i(t)); } #undef unpack constexpr long double PI = 3.141592653589793238462643383279L; template struct REC { F f; REC(F &&f_) : f(forward(f_)) {} template auto operator()(Args &&...args) const { return f(*this, forward(args)...); }}; constexpr int mod = 998244353; //constexpr int mod = 1000000007; #line 2 "library/graph/graph-template.hpp" template struct Edge { int from, to; T cost; Edge() = default; Edge(int _to, T _cost) : from(-1), to(_to), cost(_cost) {} Edge(int _from, int _to, T _cost) : from(_from), to(_to), cost(_cost) {} bool operator < (const Edge &a) const { return cost < a.cost; } bool operator > (const Edge &a) const { return cost > a.cost; } Edge &operator = (const int &x) { to = x; return *this; } operator int() const { return to; } friend ostream operator<<(ostream &os, Edge &edge) { return os << edge.to; } }; template using Edges = vector>; template using Wgraph = vector>; using Ugraph = vector>; Ugraph uinput(int N, int M = -1, bool is_directed = false, int origin = 1) { Ugraph g(N); if (M == -1) M = N - 1; while(M--) { int a,b; cin >> a >> b; a -= origin, b -= origin; g[a].push_back(b); if(!is_directed) g[b].push_back(a); } return g; } template Wgraph winput(int N, int M = -1, bool is_directed = false,int origin = 1) { Wgraph g(N); if (M == -1) M = N - 1; while(M--) { int a,b; T c; cin >> a >> b >> c; a -= origin, b -= origin; g[a].emplace_back(b,c); if(!is_directed) g[b].emplace_back(a,c); } return g; } #line 3 "library/graph/SCC.hpp" template struct SCC { private: const G &g; vector> rg; vector comp,order; vector used; vector> blng; public: vector> dag; SCC(G &_g):g(_g),used(g.size(),0){ build(); } int operator[](int k){return comp[k]; } vector &belong(int i){return blng[i]; } private: void dfs(int idx) { if(used[idx]) return; used[idx] = true; for(auto to:g[idx])dfs(int(to)); order.push_back(idx); } void rdfs(int idx,int cnt) { if(comp[idx] != -1) return; comp[idx] = cnt; for(int to:rg[idx])rdfs(to,cnt); } void build() { for(int i = 0;i < (int)g.size(); i++) dfs(i); reverse(begin(order),end(order)); used.clear(); used.shrink_to_fit(); comp.resize(g.size(),-1); rg.resize(g.size()); for(int i = 0;i < (int)g.size(); i++) { for(auto e:g[i]) { rg[(int)e].emplace_back(i); } } int ptr = 0; for(int i:order) if(comp[i] == -1) rdfs(i,ptr),ptr++; rg.clear(); rg.shrink_to_fit(); order.clear(); order.shrink_to_fit(); dag.resize(ptr); blng.resize(ptr); for(int i = 0;i < (int)g.size();i++) { blng[comp[i]].push_back(i); for(auto &to:g[i]) { int x = comp[i],y = comp[to]; if(x == y)continue; dag[x].push_back(y); } } } }; #line 100 "main.cpp" int main() { INT(n); vvi g(n); rep(i,n) { INT(m); rep(j,m) { INT(x); x--; g[i].emplace_back(x); } } SCC scc(g); if(scc[0] != 0) { No(); return 0; } vi ok((int)scc.dag.size() - 1); rep(i,n) { for(auto &j:g[i]) { if(scc[i] + 1 == scc[j]) ok[scc[i]] = 1; } } int f = 1; rep(i,ok.size()) if(ok[i] == 0) f = 0; if(f) Yes(); else No(); }