n = int(input())
S = set(range(10))
for i in range(n):
    a, b, c, d, r = map(str, input().split())
    a, b, c, d = int(a), int(b), int(c), int(d)
    if r == 'NO':
        S.discard(a)
        S.discard(b)
        S.discard(c)
        S.discard(d)
    else:
        S = S & {a, b, c, d}
S = list(S)
print(S[0])