n=int(input())
x=list(range(10))
for i in range(n):
    a,b,c,d,r = map(str,input().split())
    y=list(map(int,a+b+c+d))
    if r=="NO":
        x=list(filter(lambda z:z not in y,x))
    else:
        x=list(filter(lambda z:z in y,x))
print(x[0])