class SegTree:
    def __init__(self, init_val, ide_ele, segfunc):
        self.n = len(init_val)
        self.num = 2**(self.n-1).bit_length()
        self.ide_ele = ide_ele
        self.segfunc = segfunc
        self.seg = [ide_ele]*2*self.num
        # set_val
        for i in range(self.n):
            self.seg[i+self.num] = init_val[i]
        # built
        for i in range(self.num-1, 0, -1):
            self.seg[i] = self.segfunc(self.seg[2*i], self.seg[2*i+1])

    def update(self, k, x):
        k += self.num
        self.seg[k] = x
        while k:
            k = k >> 1
            self.seg[k] = self.segfunc(self.seg[2*k], self.seg[2*k+1])

    def query(self, l, r):
        if r <= l:
            return self.ide_ele
        l += self.num
        r += self.num
        lres = self.ide_ele
        rres = self.ide_ele
        while l < r:
            if r & 1:
                r -= 1
                rres = self.segfunc(self.seg[r], rres)
            if l & 1:
                lres = self.segfunc(lres, self.seg[l])
                l += 1
            l = l >> 1
            r = r >> 1
        res = self.segfunc(lres, rres)
        return res

    def __str__(self): # for debug
        arr = [self.query(i,i+1) for i in range(self.n)]
        return str(arr)

def segfunc(x, y):
    if x >= y:
        return x
    else:
        return y

import sys
import io, os
input = io.BytesIO(os.read(0,os.fstat(0).st_size)).readline

def main():

    n, k = map(int, input().split())
    A = [0]*n
    B = [0]*n
    for i in range(n):
        a, m = map(int, input().split())
        A[i] = a
        b = list(map(int, input().split()))
        b = [j-1 for j in b]
        B[i] = b

    ans = 0
    seg = SegTree([0]*n, 0, max)
    for i in range(n):
        temp = 0
        for b in B[i]:
            x = A[i]-A[b]+seg.query(0, b)
            temp = max(temp, x)
        seg.update(i, temp)
        ans = max(ans, temp)
    print(ans)

if __name__ == '__main__':
    main()