/* -*- coding: utf-8 -*-
 *
 * 1676.cc:  No.1676 Coin Trade (Single) - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 100000;

/* typedef */

typedef long long ll;

/* global variables */

int as[MAX_N];
ll dp[MAX_N + 1];

/* subroutines */

/* main */

int main() {
  int n, k;
  scanf("%d%d", &n, &k);

  for (int i = 0; i < n; i++) {
    int mi;
    scanf("%d%d", as + i, &mi);

    dp[i + 1] = dp[i];

    for (int j = 0; j < mi; j++) {
      int bj;
      scanf("%d", &bj), bj--;

      dp[i + 1] = max(dp[i + 1], dp[bj] + as[i] - as[bj]);
    }
  }

  printf("%lld\n", dp[n]);
  return 0;
}