n = int(input())
queries = []
for _ in range(n):
    parts = input().split()
    a, b, c, d = map(int, parts[:4])
    r = parts[4]
    nums = {a, b, c, d}
    queries.append((nums, r))

answer = -1
for candidate in range(10):
    valid = True
    for (nums, r) in queries:
        in_nums = candidate in nums
        if r == 'YES':
            if not in_nums:
                valid = False
                break
        else:
            if in_nums:
                valid = False
                break
    if valid:
        answer = candidate
        break  # Since there's only one valid answer

print(answer)