The ICPC committee would like to have its meeting as soon as possible to address every little issue of the next contest. However, members of the committee are so busy maniacally developing (possibly useless) programs that it is very difficult to arrange their schedules for the meeting. So, in order to settle the meeting date, the chairperson requested every member to send back a list of convenient dates by E-mail. Your mission is to help the chairperson, who is now dedicated to other issues of the contest, by writing a program that chooses the best date from the submitted lists. Your program should find the date convenient for the most members. If there is more than one such day, the earliest is the best.
while True:
    n, q = map(int, input().split())
    if n == 0: break
    ls = []
    for i in range(n):
        ls.append(list(map(int, input().split())))

    for i in range(1, 101):
        count = 0
        for j in range(len(ls)):
            if i in ls[j][1:]:
                count += 1
                if count == q:
                    break
        else: continue
        print(i)
        break
    else:
        print(0)
while True:
    n, q = map(int, input().split())
    if n == 0: break
    ls = []
    for i in range(n):
        ls.append(list(map(int, input().split())))

    max_q = 0
    date = 0
    for i in range(1, 101):
        count = 0
        for j in range(len(ls)):
            if i in ls[j][1:]:
                count += 1
                if count > max_q:
                    max_q = count
                    date = i
    if max_q < q:
        print(0)
    else:
        print(date)