#!/bin/python

import sys

from sets import Set
n = int(raw_input().strip())

line=True

xSet=Set()
ySet=Set()
for a0 in xrange(n):
    x,y = raw_input().strip().split(' ')
    x,y = [int(x),int(y)]
    xSet.add(x)
    ySet.add(y)
 
if len(xSet)==1 or len(ySet)==1:
    print "YES"
else:
    print "NO"