# coding:utf-8

n = int(input())

ans_list = [str(i) for i in range(10)]
taro_list = []
yes_list = []

for i in range(n):
    taro_list.append(input().split())

for j in range(n):
    if taro_list[j][4] == 'NO':
        for k in range(4):
            try:
                ans_list[ans_list.index(taro_list[j][k])] = '-'
            except ValueError:
                continue

    elif taro_list[j][4] == 'YES':
        for k in range(4):
            yes_list.append(taro_list[j][k])

if ans_list.count('-') == 9:
    ans = [i for i in ans_list if i != '-']
    print(ans[0])

elif ans_list.count('-') == 0:
    ans = [i for i in yes_list if yes_list.count(i) == 2]
    print(ans[0])

else:
    ans = [i for i in yes_list if yes_list.count(i) == 2 and i in ans_list]
    print(ans[0])