# -*- coding: utf-8 -*-


numbers = {x for x in range(10)}
N = int(input())
for i in range(N):
    n1, n2, n3, n4, flag = input().split()
    if flag == 'YES':
        numbers = numbers & {int(n1), int(n2), int(n3), int(n4)}
    else:
        numbers = numbers - {int(n1), int(n2), int(n3), int(n4)}
print(list(numbers)[0])