#!/usr/bin/env/ python
# -*- coding:utf-8 -*-

import numpy as np
import Queue

N = raw_input()
N = int(N)
mat = np.zeros([100,100], dtype=np.int8)

for i in range(N):
    ra,ca,rb,cb = raw_input().split()
    ra = int(ra)
    ca = int(ca)
    rb = int(rb)
    cb = int(cb)
    mat[ra-1,ca-1] += 1
    mat[rb-1,cb-1] += 1

YES_NO = True
flag = np.zeros([100,100],dtype=bool)
q = Queue.Queue()
exit()
for x in range(100):
    for y in range(100):
        if flag[x][y] == False and mat[x][y] > 0:
            rc = []
            edge = 0
            q.put([x,y])
            rc.append([x,y])
            flag[x][y] = True
            edge += mat[x][y]
            while not q.empty():
                pos = q.get()
                tmpx = pos[0]
                tmpy = pos[1]
                if flag[tmpx-1][tmpy] == False and mat[tmpx-1][tmpy] > 0 and tmpx>0:
                    q.put([tmpx-1,tmpy])
                    flag[tmpx-1][tmpy] = True
                    rc.append([tmpx-1,tmpy])
                    edge += mat[tmpx-1][tmpy]
                if flag[tmpx+1][tmpy] == False and mat[tmpx+1][tmpy] > 0 and tmpx<100:
                    q.put([tmpx+1,tmpy])
                    flag[tmpx+1][tmpy] = True
                    rc.append([tmpx+1,tmpy])
                    edge += mat[tmpx+1][tmpy]
                if flag[tmpx][tmpy-1] == False and mat[tmpx][tmpy-1] > 0 and tmpy>0:
                    q.put([tmpx,tmpy-1])
                    flag[tmpx][tmpy-1] = True
                    rc.append([tmpx,tmpy-1])
                    edge += mat[tmpx][tmpy-1]
                if flag[tmpx][tmpy+1] == False and mat[tmpx][tmpy+1] > 0 and tmpy<100:
                    q.put([tmpx,tmpy+1])
                    flag[tmpx][tmpy+1] = True
                    rc.append([tmpx,tmpy+1])
                    edge += mat[tmpx][tmpy+1]

            edge = edge / 2
            if edge > len(rc):
                YES_NO = False
                    
if YES_NO:
    print 'YES'
else:
    print 'NO'