N = int(input())
num = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
cand = []
answer = []
bool = False

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":
        num[int(A)] = -1
        num[int(B)] = -1
        num[int(C)] = -1
        num[int(D)] = -1
    else:
        for i in range(10):
            if num[i] != A and num[i] != B and num[i] != C and num[i] != D:
                num[i] = -1

print(max(num))