N = int(input())

states = [0 for _ in range(10)]
ns = [list(input().split()) for _ in range(N)]
for nl in ns:
    r, indexes = nl[-1], list(map(int, nl[:-1]))
    for i in indexes:
        states[i] = 2 if (r == 'NO') or not states[i] else 1

ans_index = states.index(1) if 1 in states else states.index(0)
print(ans_index)