N = int(input())
data = []
for i in range(N):
    a, b, c, d, r = input().split()
    data.append((r, int(a), int(b), int(c), int(d)))

check = [True]*10

for r, a, b, c, d in data:
    if r == 'NO':
        check[a] = False
        check[b] = False
        check[c] = False
        check[d] = False
    
    else:
        nums = set([a, b, c, d])
        for num in range(10): # a, b, c, d 以外の数字を False にする
            if num not in nums:
                check[num] = False

ans = check.index(True)
print(ans)