#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int INF = 1000000100;
const ll INFL = 2e18;
template <class T>bool chmin(T &a, T b){ if (a > b) { a = b; return true;} else return false;}
template <class T>bool chmax(T &a, T b){ if (a < b) { a = b; return true;} else return false;}

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

    vector<int> A(N);
    vector<vector<int>> B(N);
    for (int i = 0;i < N;i++) {
        cin >> A[i];
        int M;
        cin >> M;
        for (int j = 0;j < M;j++) {
            int b;
            cin >> b;
            b--;
            B[i].push_back(b);
        }
    }


    vector<ll> dp(N,0);
    for (int i = 1;i < N;i++) {
        chmax(dp[i],dp[i-1]);
        for (int j = 0;j < B[i].size();j++) {
            chmax(dp[i],dp[B[i][j]] + A[i] - A[B[i][j]]);
        }
    }

    cout << dp[N-1] << endl;
}