N = int(input())
flg = [True] * 10
for _ in range(N):
    Z = list(input().split())
    L = [int(Z[i]) for i in range(4)]
    R = Z[4]
    if R == 'NO':
        for i in L:
            flg[i] = False
    else:
        for i in range(10):
            if not i in L:
                flg[i] = False
for i in range(10):
    if flg[i]:
        print(i)
        break