#include <bits/stdc++.h>
using namespace std;
const long long INF = 1000000000000000;
int main(){
  int N, K;
  cin >> N >> K;
  vector<int> A(N), M(N);
  vector<vector<int>> B(N);
  for (int i = 0; i < N; i++){
    cin >> A[i] >> M[i];
    B[i] = vector<int>(M[i]);
    for (int j = 0; j < M[i]; j++){
      cin >> B[i][j];
      B[i][j]--;
    }
  }
  vector<long long> dp(N, 0);
  vector<long long> mx(N, 0);
  for (int i = 1; i < N; i++){
    for (int j = 0; j < M[i]; j++){
      dp[i] = max(dp[i], mx[B[i][j]] + A[i] - A[B[i][j]]);
    }
    mx[i] = max(mx[i - 1], dp[i]);
  }
  cout << mx[N - 1] << endl;
}