n=input()
t=[]
for _ in[0]*n:
	a,b,c,d,x=raw_input().split()
	if x=="NO":
		if len(t)==0:
			t=[`i`for i in range(10)]
		if a in t:t.remove(a)
		if b in t:t.remove(b)
		if c in t:t.remove(c)
		if d in t:t.remove(d)
	else:
		if len(t)==0:
			t=[a,b,c,d]
		t=[i for i in[a,b,c,d]if i in t]
print t[0]