N = int(input())
A = [input().split() for _ in range(N)]

yes = [set(map(int, front)) for *front, tail in A if tail == "YES"]
no = [set(map(int, front)) for *front, tail in A if tail == "NO"]

overt = set(range(10))
for s in yes:
  overt &= s

potential = set(range(10))
for s in no:
  potential -= s

print((potential & overt).pop())