#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<bitset>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<deque>
#include<list>
#include<iomanip>
#include<cmath>
#include<cstring>
#include<functional>
#include<cstdio>
#include<cstdlib>
#include<numeric>
#include<ctime>
//#include<atcoder/all>
using namespace std;
//using namespace atcoder;

#define repr(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rep(i, n) repr(i, 0, n)
#define INF 2e9
//#define MOD 1000000007
#define MOD 998244353
#define LINF (long long)4e18
#define jck 3.141592
#define PI acos(-1.0)

const double EPS = 1e-18;

using ll = long long;
using Pi = pair<int,int>;
using Pl = pair<ll,ll>;
//using mint = modint998244353;

int dh[] = {-1,1,0,0};
int dw[] = {0,0,1,-1};


int main(){
    int n,k; cin >> n >> k;
    vector<int> a(n);
    vector<vector<int>> bb(n);
    rep(i,n){
        cin >> a[i];
        int m; cin >> m;
        rep(j,m){
            int b; cin >> b;
            b--;
            bb[i].push_back(b);
        }
    }
    vector<ll> dp(n);
    repr(i,1,n){
        dp[i] = max(dp[i],dp[i-1]);
        rep(j,bb[i].size()){
            int pre = bb[i][j];
            dp[i] = max(dp[i],dp[pre]+a[i]-a[pre]);
        }
    }
    cout << dp[n-1] << endl;
}