#include <bits/stdc++.h>
#define rep(i, l, r) for (int i = (l); i < (r); i++)
using namespace std;

typedef long long ll;

int main() {
    int N, K;
    cin >> N >> K;
    vector<ll> A(N), M(N), dp(N + 1, 0);
    vector<vector<int>> B(N);
    rep(i, 0, N) {
        cin >> A[i] >> M[i];
        rep(j, 0, M[i]) {
            B[i].push_back(0);
            cin >> B[i].back();
        }
    }
    rep(i, 0, N) {
        dp[i + 1] = dp[i];
        rep(j, 0, M[i]) {
            dp[i + 1] = max(dp[i + 1], dp[B[i][j]] + A[i] - A[B[i][j] - 1]);
        }
    }
    cout << dp[N] << endl;
    //rep(i, 0, N + 1) cout << "dp[" << i << "]=" << dp[i] << endl;
}