N=int(input())
i=0
A=[]
for i in range(N):
    A.append(input().split())
    i+=1
y=0
i=0
K=["0","1","2","3","4","5","6","7","8","9"]
while y==0 and i<N:
    if A[i][4]=="YES":
        K=A[i][:-1]
   #     print (K)
        y=1
    i=i+1
if i==N:
    i=0
while len(K)>1:
    if i==N-1:
        i=0
    else:
        i+=1
    j=0
    while len(K)>1 and j<len(K):
        m=0
        ex=0
        while ex==0 and m<4:
      #      print(K[j])
  #          print (i)
            if K[j]==A[i][m]:
  #              print(A[i][m])
                if A[i][4]=="NO":
                    K.pop(j)
                    j-=1
                ex=1
            else:
                m+=1
        if ex==0:
            if A[i][4]=="YES":
                K.pop(j)
                j-=1
      #          print(j)      
        j+=1
  #  print(K)
print(K[0])