N=int(input())
A=[0,1,2,3,4,5,6,7,8,9]
F=[1,1,1,1,1,1,1,1,1,1]

for _ in range(N):
    tmp=input().split()
    rep=tmp.pop()
    tmp=map(int,tmp)
    tmp=sorted(tmp)
    if rep=='NO':
        for x in tmp:
            F[x]=0
    else:
        for x in A:
            if x not in tmp:
                F[x]=0
            
print(F.index(1))
#print(*A)