N = int(input())
inp = []
for i in range(N):
    inp.append(input().split())
    
cards = list('0123456789')
pos = []

for t in inp:
    isIn = t.pop(-1)
    if isIn == "NO":
        for n in t:
            cards.remove(n)
    else:
        pos.extend(t)
        
if len(cards) == 1:
    ans = cards[0]
elif len(set(cards) & set(pos)) == 1:
    ans = set(cards) & set(pos)
else:
    ans = cards[0]
    
print(ans)