N = int(input())
number_list = list(range(10))

if 2 <= N <= 6:
    for i in range(N):
        *numbers, answer = input().split()
        numbers = [int(num) for num in numbers]

        if answer == "NO":
            for num in numbers:
                if num in number_list:
                     number_list.remove(num)

print(number_list[0])