#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using Graph=vector<vector<int>>;
#define INF 1000000000

int main(){
  int N,K;
  cin>>N>>K;
  vector<ll> A(N);
  vector<int> M(N);
  vector<vector<int>> B(N);
  for(int i=0;i<N;i++){
    cin>>A[i]>>M[i];
    B[i].resize(M[i]);
    for(int j=0;j<M[i];j++){
      cin>>B[i][j];
      B[i][j]--;
    }
  }

  vector<ll> dp(N+1,0);
  for(int i=0;i<N;i++){
    dp[i+1]=dp[i];
    for(int j=0;j<M[i];j++){
      dp[i+1]=max<ll>(dp[i+1],dp[B[i][j]]+A[i]-A[B[i][j]]);
    }
  }
  cout<<dp[N]<<'\n';
}