Sy = set(str(i) for i in range(10))
Sn = set(str(i) for i in range(10))

N = int(input())

for _ in range(N):
    lst = input().split()
    if lst[-1][0] == "Y":
        Sy = Sy.intersection(lst[:-1])
    else:
        Sn = Sn.difference(lst[:-1])

if len(Sy) == 1:
    print(Sy.pop())
else:
    print(Sn.pop())