#coding:utf-8

N=input()
list=[raw_input().split() for i in range(N)]

no=[]
yes=[]
for i in list:
	if i[4] == 'NO':
		for u in i[:4]:
			no.append(u)
	else:
		for u in i[:4]:
			yes.append(u)

if no and not yes:
	for i in range(10):
		if str(i) not in no:
			print i
			break
elif not no and yes:
	for i in yes:
		if 2 <= yes.count(i):
			print i
			break
else:
	for i in yes:
		if i not in no and len(yes)/4 <= yes.count(i):
			print i
			break