N = int(input())
D = [list(input().split()) for x in range(N)]
C = set(['1', '2', '4', '5', '6', '7', '8', '9', '0'])

for m in range(N):
    if D[m][4] == 'NO':
        F = set(D[m][:4])
        C -= F
    else:
        F = set(D[m][:4])
        C = C.intersection(F)

print(list(C)[0])