n = int(input())
yes = []
no = []
y_flag = 0
n_flag = 0
for i in range(n):
	a = input().split()
	if a[-1] == 'YES':
		yes.extend(a[:-1])
		y_flag += 1
	else:
		no.extend(a[:-1])
		n_flag += 1
yes = [_ for _ in set(yes) if yes.count(_) > 1]
if y_flag == 0:
	print(''.join([str(i) for i in range(0, 10) if str(i) not in no]))
	exit()
elif n_flag == 0:
	print(''.join(yes))
	exit()
for i in range(len(yes)):
	if yes[i] not in no:
		print(yes[i])
		exit()