import collections


def sort_out(turn, yes_list, no_list):
    for _ in range(turn):
        answer = list(input().split())
        popped_item = answer.pop(4)
        if popped_item == "NO":
            no_list += answer
        else:
            yes_list += answer
    single_number_list = sorted(list(map(int, set(no_list))))
    befor_processing_double_number_list = sorted(list(map(int, yes_list)))
    double_number_list = [
        key
        for key, val in collections.Counter(befor_processing_double_number_list).items()
        if val > 1
    ]
    return single_number_list, double_number_list


def guess_number(sorted_no_list, sorted_yes_list):
    number_list = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
    if sorted_no_list:
        not_much_number = list(map(int, set(number_list) - set(sorted_no_list)))
        if sorted_yes_list:
            much_number = list(map(int, set(not_much_number) & set(sorted_yes_list)))
            return much_number
        else:
            return not_much_number
    else:
        much_number = list(map(int, set(number_list) & set(sorted_yes_list)))
        return much_number


def main():
    turn = int(input())
    no_list = []
    yes_list = []
    sorted_no_list, sorted_yes_list = sort_out(turn, yes_list, no_list)
    answer = guess_number(sorted_no_list, sorted_yes_list)
    print(answer[0])


if __name__ == "__main__":
    main()