#include<bits/stdc++.h>
#include<random>
using namespace std;
//#define int long long
#define REP(i,m,n) for(int i=(m);i<(n);i++)
#define rep(i,n) REP(i,0,n)
#define pb push_back
#define all(a) a.begin(),a.end()
#define rall(c) (c).rbegin(),(c).rend()
#define mp make_pair
#define endl '\n'
//#define vec vector<ll>
//#define mat vector<vector<ll> >
#define fi first
#define se second
//#define double long double
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> pll;
//typedef long double ld;
typedef complex<double> Complex;
const ll INF=1e9+7;
const ll MOD=998244353;
const ll inf=INF*INF;
const ll mod=MOD;
const ll MAX=1000000;
const double PI=acos(-1.0);
typedef vector<vector<ll> > mat;
typedef vector<ll> vec;



void solve(){
    ll n,k;cin>>n>>k;
    vector<ll>a(n),m(n);
    vector<vector<ll> >b(n);
    rep(i,n){
        cin>>a[i]>>m[i];
        rep(j,m[i]){
            ll c;cin>>c;
            c--;
            b[i].pb(c);
        }
    }
    vector<ll>dp(n,-1);
    ll ans=0;
    rep(i,n){
        dp[i]=0;
        if(i)dp[i]=max(dp[i],dp[i-1]);
        rep(j,m[i]){
            dp[i]=max(dp[i],dp[b[i][j]] + a[i]-a[b[i][j]]);
        }
        ans=max(ans,dp[i]);
    }
    cout<<ans<<endl;
}

signed main(){
    solve();
}