#include <bits/stdc++.h>
using namespace std;
template <typename T, typename U>
std::istream& operator>>(std::istream& i, pair<T, U>& p) {
  i >> p.first >> p.second;
  return i;
}
template <typename T>
std::istream& operator>>(std::istream& i, vector<T>& t) {
  for (auto& v : t) {
    i >> v;
  }
  return i;
}
template <typename T, typename U>
std::ostream& operator<<(std::ostream& o, const pair<T, U>& p) {
  o << p.first << ' ' << p.second;
  return o;
}
template <typename T>
std::ostream& operator<<(std::ostream& o, const vector<T>& t) {
  if (t.empty()) o << '\n';
  for (size_t i = 0; i < t.size(); ++i) {
    o << t[i] << " \n"[i == t.size() - 1];
  }
  return o;
}
template <typename T>
using minheap = priority_queue<T, vector<T>, greater<T>>;
template <typename T>
using maxheap = priority_queue<T, vector<T>, less<T>>;
unsigned int logceil(long long first) {
  return first ? 8 * sizeof(long long) - __builtin_clzll(first) : 0;
}
namespace std {
template <typename T, typename U>
struct hash<pair<T, U>> {
  hash<T> t;
  hash<U> u;
  size_t operator()(const pair<T, U>& p) const {
    return t(p.first) ^ (u(p.second) << 7);
  }
};
}  // namespace std
template <typename T, typename F>
T bsh(T l, T h, const F& f) {
  T r = -1, m;
  while (l <= h) {
    m = (l + h) / 2;
    if (f(m)) {
      l = m + 1;
      r = m;
    } else {
      h = m - 1;
    }
  }
  return r;
}
template <typename F>
double bshd(double l, double h, const F& f, double p = 1e-9) {
  unsigned int r = 3 + (unsigned int)log2((h - l) / p);
  while (r--) {
    double m = (l + h) / 2;
    if (f(m)) {
      l = m;
    } else {
      h = m;
    }
  }
  return (l + h) / 2;
}
template <typename T, typename F>
T bsl(T l, T h, const F& f) {
  T r = -1, m;
  while (l <= h) {
    m = (l + h) / 2;
    if (f(m)) {
      h = m - 1;
      r = m;
    } else {
      l = m + 1;
    }
  }
  return r;
}
template <typename F>
double bsld(double l, double h, const F& f) {
  unsigned int r = 200;
  while (r--) {
    double m = (l + h) / 2;
    if (f(m)) {
      h = m;
    } else {
      l = m;
    }
  }
  return (l + h) / 2;
}
template <typename T>
T gcd(T a, T b) {
  if (a < b) swap(a, b);
  return b ? gcd(b, a % b) : a;
}
template <typename T>
class vector2 : public vector<vector<T>> {
 public:
  vector2() {}
  vector2(size_t a, size_t b, T t = T())
      : vector<vector<T>>(a, vector<T>(b, t)) {}
};
template <typename T>
class vector3 : public vector<vector2<T>> {
 public:
  vector3() {}
  vector3(size_t a, size_t b, size_t c, T t = T())
      : vector<vector2<T>>(a, vector2<T>(b, c, t)) {}
};
template <typename T>
class vector4 : public vector<vector3<T>> {
 public:
  vector4() {}
  vector4(size_t a, size_t b, size_t c, size_t d, T t = T())
      : vector<vector3<T>>(a, vector3<T>(b, c, d, t)) {}
};
template <typename T>
class vector5 : public vector<vector4<T>> {
 public:
  vector5() {}
  vector5(size_t a, size_t b, size_t c, size_t d, size_t e, T t = T())
      : vector<vector4<T>>(a, vector4<T>(b, c, d, e, t)) {}
};
template <typename T>
struct bounded_priority_queue {
  inline bounded_priority_queue(unsigned int X) : A(X), B(0), s(0) {}
  inline void push(unsigned int L, T V) {
    B = max(B, L);
    A[L].push(V);
    ++s;
  }
  inline const T& top() const { return A[B].front(); }
  inline void pop() {
    --s;
    A[B].pop();
    while (B > 0 && A[B].empty()) --B;
  }
  inline bool empty() const { return A[B].empty(); }
  inline void clear() {
    s = B = 0;
    for (auto& a : A) a = queue<T>();
  }
  inline unsigned int size() const { return s; }

 private:
  vector<queue<T>> A;
  unsigned int B;
  int s;
};
struct UnionFind {
  UnionFind(size_t N) : P(N, -1), comp(N) {}
  int find(int first) {
    while (P[first] > 0) {
      first = P[first] - 1;
    }
    return first;
  }
  bool united(int first, int second) { return find(first) == find(second); }
  bool unite(int first, int second) {
    first = find(first);
    second = find(second);
    if (first == second) {
      return false;
    }
    --comp;
    if (P[first] > P[second]) {
      swap(first, second);
    }
    P[first] += P[second];
    P[second] = first + 1;
    return true;
  }
  inline unsigned int size(int u) { return -P[find(u)]; }
  vector<int> P;
  size_t comp;
};
class EAvoidRainbowCycles {
 public:
  void solve(istream& cin, ostream& cout) {
    int N, M;
    cin >> M >> N;
    vector<pair<int, vector<int>>> S(M);
    for (int i = 0; i < M; ++i) cin >> S[i].first;
    vector<std::pair<int, int>> ByCost(N);
    for (int i = 0; i < N; ++i) {
      int c;
      cin >> c;
      ByCost[i] = {c, i};
    }
    sort(ByCost.rbegin(), ByCost.rend());
    vector<int> ID(N);
    for (int i = 0; i < N; ++i) ID[ByCost[i].second] = i;
    for (int i = 0; i < M; ++i) {
      int s;
      cin >> s;
      for (int j = 0; j < s; ++j) {
        int first;
        cin >> first;
        S[i].second.push_back(ID[first - 1]);
      }
      sort(S[i].second.begin(), S[i].second.end());
    }
    sort(S.rbegin(), S.rend());
    vector<pair<int, std::pair<int, int>>> E;
    for (int i = 0; i < M; ++i) {
      for (int j = 1; j < S[i].second.size(); ++j) {
        E.push_back({S[i].first + ByCost[S[i].second[j]].first,
                     {S[i].second[0], S[i].second[j]}});
      }
    }
    sort(E.rbegin(), E.rend());
    UnionFind UF(N);
    long long ans = 0;
    for (auto e : E) {
      if (!UF.unite(e.second.first, e.second.second)) ans += e.first;
    }
    cout << ans << '\n';
  }
};
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  EAvoidRainbowCycles solver;
  std::istream& in(std::cin);
  std::ostream& out(std::cout);
  solver.solve(in, out);
  return 0;
}
