lst = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]
delete = []
n = int(input())
for i in range(n):
    s = input().split()
    if s[4] == "YES":
        for value in lst:
            if not value in s[0:-1]:
                lst[(lst.index(value))]=""
    else:
        for value in s[0:-1]:
            if value in lst:
                lst.remove(value)
lst = sorted(lst, reverse=1)
print(lst[0])