# coding:utf-8

n = int(input())
yes_list = []
no_list = [str(i) for i in range(10)]
taro_list = []

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

for k in range(0,n):
    if taro_list[k][4] == 'YES':
        for l in taro_list[k][0:4]:
            yes_list.append(l)
    elif taro_list[k][4] == 'NO':
        for l in range(len(no_list)):
            if no_list[l] in taro_list[k][0:4]:
                    no_list[l] = '-'
            else:
                continue

if yes_list != []:
    for m in yes_list:
        if yes_list.count(str(m)) > 1:
            print(m)
            break
        else:
            continue
else:
    for m in no_list:
        if m == '-':
            continue
        else:
            print(m)