n, k = map(int, input().split())
inf = 10 ** 20
dp = [0] * (n + 1)
alst = [0] * (n + 1)
for i in range(1, n + 1):
    a, m = map(int, input().split())
    alst[i] = a
    blst = list(map(int, input().split()))
    dp[i] = dp[i - 1]
    for b in blst:
        dp[i] = max(dp[i], dp[b] + a - alst[b])

print(dp[-1])