N, K = map(int, input().split())
A = []
M = []
B = []

for i in range(N):
    a, m = map(int, input().split())
    A.append(a)
    M.append(m)
    B.append([i - 1 for i in list(map(int, input().split()))])

E = [[(i + 1, 0)] for i in range(N - 1)] + [[]]
for i in reversed(range(N)):
    for b in B[i]:
        if A[b] < A[i]:
            E[b].append((i, A[i] - A[b]))

dp = [0] * N
for i in range(N):
    for j, c in E[i]:
        dp[j] = max(dp[j], dp[i] + c)

print(dp[-1])