N = int(input())
L = [list(map(int,input().split())) for i in range(N)]

a = [2,8]
b = [3,9]
c = [7,9]

for k in L :
    l = k[:2]
    l2 = k[2:]
    if a == l :
        a = l2
    elif b == l :
        b = l2
    elif c == l :
        c = l2

if a == [5,8] and b == [4,8] and c == [6,8] :
    print("YES")
else :
    print("NO")