uni=["0","1","2","3","4","5","6","7","8","9"]

N=int(input())
A=[]
for _ in range(N):
    A=(input().split())
    if A[4]=="YES":
        ans=[]
        for j in range(4):
            if A[j] in uni:
                ans.append(A[j])
        uni=ans
    else:
        for j in range(4):
            if A[j] in uni:
                uni.remove(A[j])

print(uni[0])