#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i,n)for (int i = 0; i < int(n); ++i)
#define rrep(i,n)for (int i = int(n)-1; i >= 0; --i)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
template<class T> void chmax(T& a, const T& b) {a = max(a, b);}
template<class T> void chmin(T& a, const T& b) {a = min(a, b);}
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, k;
    cin >> n >> k;
    VL dp(n + 1);
    VI a(n);
    rep(i, n) {
        int m;
        cin >> a[i] >> m;
        ll mn = dp[i];
        rep(_, m) {
            int b;
            cin >> b;
            b--;
            chmin(mn, dp[b + 1] + a[b] - a[i]);
        }
        dp[i + 1] = mn;
    }
    cout << -dp[n] << endl;
}