#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;

//template
#define rep(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define ALL(v) (v).begin(),(v).end()
using ll=long long int;
const int inf = 0x3fffffff; const ll INF = 0x1fffffffffffffff; const double eps=1e-12;
template<typename T>inline bool chmax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
template<typename T>inline bool chmin(T& a,T b){if(a>b){a=b;return 1;}return 0;}



int main(){
   int n,k;
   cin>>n>>k;
   vector g(n,vector<int>());
   vector<int> a(n);
   rep(i,0,n){
      int m;
      cin>>a[i]>>m;
      rep(j,0,m){
         int p;
         cin>>p;
         g[p-1].push_back(i);
      }
   }

   vector<ll> dp(n,-INF);
   dp[0]=0;
   rep(i,0,n){
      if(i!=n-1)chmax(dp[i+1],dp[i]);
      for(auto& to:g[i])chmax(dp[to],dp[i]+max(0,a[to]-a[i]));
   }
   cout<<dp[n-1]<<'\n';
   return 0;
}