def test():
    N = int(input())
    list1 = [0,1,2,3,4,5,6,7,8,9]
    list2 = []

    for i in range(N):
        list2 = (input().split())
        if "NO" in list2:
            for j in range(4):
                if int(list2[j]) in list1:
                    list1.remove(int(list2[j]))
                else:
                    pass
        if "YES" in list2:
            for k in range(10):
                if str(k) not in list2:
                    if k in list1:
                        list1.remove(k)
                    else:
                        pass

    print(list1[0])


if __name__ == "__main__":
    test()