n = int(input())

rc_dic = {}

for _ in range(n):
    r0, c0, r1, c1 = tuple(int(x) for x in input().split())

    if (r0, c0) not in rc_dic:
        rc_dic[(r0, c0)] = True
    elif (r1, c1) not in rc_dic:
        rc_dic[(r1, c1)] = True
    else:
        print("NO")
        exit()

print("YES")