n = int(input())
b = set(map(str,range(10)))
for i in range(n):
    a1,a2,a3,a4,r = input().split()
    c = {a1,a2,a3,a4}
    if r == "NO":
        b = b - c
    else:
        b = b & c
print(int(list(b)[0]))