//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,avx512f")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <immintrin.h>
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <complex>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#ifdef DEBUG
#include "./CompetitiveProgrammingCpp/Timer.hpp"
#include "./CompetitiveProgrammingCpp/debug.hpp"
#include "./CompetitiveProgrammingCpp/sample.hpp"
#else
#define dump(...)
#endif

/* macro */
#define FOR(i, b, e) for (ll i = (ll)(b); i < (ll)(e); ++i)
#define RFOR(i, b, e) for (ll i = (ll)(e - 1); i >= (ll)(b); --i)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) RFOR(i, 0, n)
#define REPC(x, c) for (const auto& x : (c))
#define REPI2(it, b, e) for (auto it = (b); it != (e); ++it)
#define REPI(it, c) REPI2(it, (c).begin(), (c).end())
#define RREPI(it, c) REPI2(it, (c).rbegin(), (c).rend())
#define REPI_ERACE2(it, b, e) for (auto it = (b); it != (e);)
#define REPI_ERACE(it, c) REPI_ERACE2(it, (c).begin(), (c).end())
#define ALL(x) (x).begin(), (x).end()
#define cauto const auto&
/* macro func */
template <class T>
inline auto sort(T& t) {
  std::sort(ALL(t));
}
template <class T>
inline auto rsort(T& t) {
  std::sort((t).rbegin(), (t).rend());
}
template <class T>
inline auto unique(T& t) {
  (t).erase(unique((t).begin(), (t).end()), (t).end());
}
template <class T, class S>
inline auto chmax(T& t, const S& s) {
  if (s > t) {
    t = s;
    return true;
  }
  return false;
}
template <class T, class S>
inline auto chmin(T& t, const S& s) {
  if (s < t) {
    t = s;
    return true;
  }
  return false;
}
inline auto BR() { std::cout << "\n"; }

/* type define */
using ll = long long;
using PAIR = std::pair<ll, ll>;
using VS = std::vector<std::string>;
using VL = std::vector<long long>;
using VVL = std::vector<VL>;
using VVVL = std::vector<VVL>;
using VD = std::vector<double>;
template <class T>
using V = std::vector<T>;

/* using std */
using std::cout;
constexpr char endl = '\n';
using std::bitset;
using std::cin;
using std::list;
using std::map;
using std::multimap;
using std::multiset;
using std::pair;
using std::priority_queue;
using std::queue;
using std::set;
using std::stack;
using std::string;
using std::unordered_map;
using std::unordered_multimap;
using std::unordered_multiset;
using std::unordered_set;
using std::vector;

/* Initial processing  */
struct Preprocessing {
  Preprocessing() {
    std::cin.tie(0);
    std::ios::sync_with_stdio(0);
  };
} _Preprocessing;

/* Remove the source of the bug */
signed pow(signed, signed) {
  assert(false);
  return -1;
}

/* define hash */
namespace std {
template <>
class hash<std::pair<ll, ll>> {
 public:
  size_t operator()(const std::pair<ll, ll>& x) const {
    return hash<ll>()(1000000000 * x.first + x.second);
  }
};
}  // namespace std

/* input */
template <class T>
std::istream& operator>>(std::istream& is, vector<T>& vec) {
  for (T& x : vec) is >> x;
  return is;
}

/* constant value */
constexpr ll MOD = 1000000007;
// constexpr ll MOD = 998244353;

//=============================================================================================

auto solve(ll n, const V<pair<PAIR, ll>>& v) {
  VL ans(n + 1, 1e18);
  auto bits = [&](ll sz, const VL& p) {
    REP(i, (1 << sz)) {
      VL x, y;
      x.reserve(sz);
      y.reserve(sz);
      REP(j, sz) {
	if ((i >> j) & 1) {
	  x.emplace_back(v[p[j]].first.first);
	} else {
	  y.emplace_back(v[p[j]].first.second);
	}
      }
      ll cst = 0;
      for (cauto[xy, tt] : v) {
	cauto[xx, yy] = xy;
	ll tmp = std::min(std::abs(xx), std::abs(yy));
	REPC(t, x) { chmin(tmp, std::abs(t - xx)); }
	REPC(t, y) { chmin(tmp, std::abs(t - yy)); }
	cst += tmp * tt;
      }
      if (cst == 600) {
	auto k = std::bitset<3>(i);
      }
      chmin(ans[sz], cst);
    }
  };

  FOR(sz, 1, n + 1) {
    VL p(sz);
    auto add = [&]() {
      ll i = sz - 1;
      ++p[i];
      while (p[i] + (sz - i - 1) == n) {
	--i;
	if (i == -1) {
	  return false;
	}
	++p[i];
      }
      FOR(k, i + 1, sz) { p[k] = p[k - 1] + 1; }
      return p[sz - 1] < n;
    };

    std::iota(ALL(p), 0);
    do {
      bits(sz, p);
    } while (add());
  }

  ans[0] = 0;
  for (cauto[xy, tt] : v) {
    cauto[x, y] = xy;
    ans[0] += std::min(std::abs(x), std::abs(y)) * tt;
  }
  return ans;
}

class UnionFind {
  std::vector<ll> m_root;
  std::vector<ll> m_depth;
  std::vector<ll> m_size;

 public:
  UnionFind(ll size_) : m_root(size_), m_depth(size_, 0), m_size(size_, 1) {
    std::iota(m_root.begin(), m_root.end(), 0);
  }
  void unite(ll x, ll y) {
    x = root(x);
    y = root(y);
    if (x == y) return;
    ll t = size(x) + size(y);
    m_size[x] = m_size[y] = t;
    if (m_depth[x] < m_depth[y])
      m_root[x] = y;
    else
      m_root[y] = x;
    if (m_depth[x] == m_depth[y]) ++m_depth[x];
  }
  bool isSame(ll x, ll y) { return root(x) == root(y); }
  ll root(ll x) {
    if (m_root[x] == x) return x;
    return m_root[x] = root(m_root[x]);
  }
  ll size(ll x) {
    if (m_root[x] == x) return m_size[x];
    return size(m_root[x] = root(m_root[x]));
  }
};

signed main() {
  ll n, m;
  cin >> n >> m;
  auto tree = UnionFind(m + n);
  VL check(n);
  REP(i, n) {
    ll k;
    cin >> k;
    REP(_, k) {
      ll l;
      cin >> l;
      --l;
      tree.unite(i, n + l);
      check[i] = l;
    }
  }
  FOR(i, 1, n) if (!tree.isSame(0, i)) {
    cout << "NO" << endl;
    return 0;
  }
  cout << "YES" << endl;
}


Measured memory_bytes: 8644