n = int(input())
ans = set(range(10))

num_ok = set(range(10))
num_ng = set()
for _ in range(n):
    num = input().split()
    if num.pop() == 'YES':
        num_ok = num_ok & set([int(x) for x in num])
    else:
        num_ng = num_ng | set([int(x) for x in num])
print(((ans - num_ng) & num_ok).pop())