num = [i for i in "0123456789"]
n = int(input())
for i in range(n):
    ans = input().split(" ")
    if ans[4] == "NO":
        for j in ans[0:4]:
            if j in num:
                num.remove(j)
    else:
        lst = []
        for k in ans[0:4]:
            if k in num:
                lst.append(k)
        num = lst
print(num[0])