n = int(input())
org_list = list('0123456789')

for i in range(n):
    inputed_list = list(input().split())
    if inputed_list[-1] == 'NO':
        for i in range(len(inputed_list) - 1):
            if inputed_list[i] in org_list:
                org_list.remove(inputed_list[i])
    else:
        tmp_list = list('0123456789')
        for i in range(len(inputed_list) - 1):
            if inputed_list[i] in tmp_list:
                tmp_list.remove(inputed_list[i])

        for e in tmp_list:
            if e in org_list:
                org_list.remove(e)

print(org_list[0])