N = int(input())
e = [[i for i in input().split()] for i in range(N)]

ABCD = [0 for i in range(N)]
R = [0 for i in range(N)]

ans = set(range(10))

for i in range(N):
    ei = e[i]
    tmp = set(map(int, ei[:4]))

    if ei[4] == "YES":
        ans = ans.intersection(tmp)
    
    else:
        ans = ans.difference(tmp)

print(int(list(ans)[0]))