#!/bin/python

import sys
from itertools import*

a=[]
b=[]
flag=0
flag1=0
count=0
count1=0
n = int(raw_input().strip())
for a0 in xrange(n):
    x,y = raw_input().strip().split(' ')
    x,y = [int(x),int(y)]
    a.append(x)
    b.append(y)
a1=a[0]
b1=b[0] 
for i in a:
    if (i == a1): 
       count=count+1
if(count==len(a)):
    flag=1
for j in b:
    if (j == b1):
       count1=count1+1
if(count1==len(b)):
    flag1=1
if(flag==1 or flag1==1):
    print "YES"
else:
    print  "NO"