import sys
input = sys.stdin.buffer.readline

def main():
    N,K = map(int,input().split())
    A = []; M = []
    RG = []
    for i in range(N):
        a,m = map(int,input().split())
        A.append(a)
        M.append(m)
        B = list(map(int,input().split()))
        B = [b-1 for b in B] #0index
        RG.append(B)

    dp = [0]*(N+1)
    for i in range(N):
        dp[i+1] = max(dp[i+1],dp[i]) #何もしない
        #print(A[i],RG[i])
        for pre in RG[i]:
            if pre < i and A[pre] < A[i]: #前のほうが安いなら。
                dif = A[i] - A[pre]
                dp[i+1] = max(dp[i+1], dp[pre] + dif)
    #print(dp)
    ans = dp[N]
    print(ans)

    
    
if __name__ == '__main__':
    main()