#include <bits/stdc++.h>
using namespace std;

# define REP(i,n) for (int i=0;i<(n);++i)
# define rep(i,a,b) for(int i=a;i<(b);++i)
# define p(s) std::cout << s ;
# define pl(s)  std::cout << s << endl;
# define printIf(j,s1,s2) cout << (j ? s1 : s2) << endl;
# define YES(j) cout << (j ? "YES" : "NO") << endl;
# define Yes(j) std::cout << (j ? "Yes" : "No") << endl;
# define yes(j) std::cout << (j ? "yes" : "no") << endl;
# define all(v) v.begin(),v.end()
# define showVector(v) REP(i,v.size()){p(v[i]);p(" ")} pl("")
template<class T> inline bool chmin(T &a, T b){ if(a > b) { a = b; return true;} return false;}
template<class T> inline bool chmax(T &a, T b){ if(a < b) { a = b; return true;} return false;}
typedef long long int ll;
typedef pair<ll,ll> P_ii;
typedef pair<double,double> P_dd;

template<class T>
vector<T> make_vec(size_t a){
    return vector<T>(a);
}

template<class T, class... Ts>
auto make_vec(size_t a, Ts... ts){
  return vector<decltype(make_vec<T>(ts...))>(a, make_vec<T>(ts...));
}

template<typename T,typename V>
typename enable_if<is_class<T>::value==0>::type
fill_v(T &t,const V &v){t=v;}

template<typename T,typename V>
typename enable_if<is_class<T>::value!=0>::type
fill_v(T &t,const V &v){
  for(auto &e:t) fill_v(e,v);
}


const int MOD = 1000000007;
const int inf=1e9+7;
const ll longinf=1LL<<60 ;

void addM(long long &a, long long b) {
    a += b;
    if (a >= MOD) a -= MOD;
}

void mulM(long long &a, long long b) {
    a = ((a%MOD)*(b%MOD))%MOD ;
}

// a^b mod M
long myPow(long a,long b,int M) {
    long ret = 1;
    long tmp = a;
    while(b>0) {
        if((b&1)==1) ret = (ret * tmp) % M;
        tmp = (tmp * tmp) % M;
        b = b>>1;
    }
    return ret;
}

 // nCk mod M
int nCk(int n,int k,int M) {
    long ret = 1;
    int mi = min(k, n-k);
    for(int i=1;i<=mi;i++) {
        ret = (ret * myPow(i,M-2,M)) % M;
    }
    for(int i=n-mi+1;i<=n;i++) {
        ret = (ret * i) % M;
    }
    return (int)ret;
};

vector<pair<long long, long long> > prime_factorize(long long n) {
    vector<pair<long long, long long> > res;
    for (long long p = 2; p * p <= n; ++p) {
        if (n % p != 0) continue;
        int num = 0;
        while (n % p == 0) { ++num; n /= p; }
        res.push_back(make_pair(p, num));
    }
    if (n != 1) res.push_back(make_pair(n, 1));
    return res;
}

bool isVistedP[100005];
bool isVistedL[100005];

int main() {
    int N,M;
    cin >> N >> M;

    vector<int> g1[N];
    vector<int> g2[M];

    REP(i,N){
        int K;
        cin >> K;
        REP(j,K) {
            int L;
            cin >> L;

            g1[i].push_back(L-1);
            g2[L-1].push_back(i);
        }
    }

    queue<int> que;
    queue<int> n_que;

    que.push(0);
    isVistedP[0] = true;

    int now = 0; // 0の時、人→言語。１の時、言語→人
    while(que.size()>0){
        while (que.size()>0){
            auto q = que.front();que.pop();

            if(now==0){
                for(auto L:g1[q]){
                    if(isVistedL[L]) continue;
                    isVistedL[L] = true;
                    n_que.push(L);
                }
            } else {
                for(auto P:g2[q]){
                    if(isVistedP[P]) continue;
                    isVistedP[P] = true;
                    n_que.push(P);
                }
            }
        }   

        while (n_que.size()>0){
            que.push(n_que.front());
            n_que.pop();
        }

        now = 1 - now;
    }

    bool ans = true;
    REP(i,N) if(!isVistedP[i]) ans = false;

    YES(ans)

    return 0;
}

Measured memory_bytes: 8952