n = int(input())
z=[""] * 100
z[28] = "A"
z[39] = "B"
z[79] = "C"
for i in range(n):
	A = list(map(str,input().split()))
	m = int(A[0] + A[1])
	l = int(A[2] + A[3])
	z[l],z[m]=z[m],""
if z[58]+z[48]+z[68] == "ABC":
    print("YES")
else:
    print("NO")