n=int(input())
lst0=[0]*10
for i in range(n):
    cur=0
    tn=list(input().split())
    tn.sort()
    if tn[4]=="NO":
        for i in range(4):
            ix=int(tn[i])
            lst0[ix]=1
    else:
        for i in range(10):
            if cur==0 and i !=int(tn[cur]):
                lst0[i]=1
            elif cur==1 and i !=int(tn[cur]):
                lst0[i]=1
            elif cur==2 and i !=int(tn[cur]):
                lst0[i]=1
            elif cur==3 and i !=int(tn[cur]):
                lst0[i]=1
            else:
                cur+=1
print(lst0.index(0))