#!/bin/python

import sys


n = int(raw_input().strip())
xs=[]
ys=[]
for a0 in xrange(n):
    x,y = map(int, raw_input().strip().split())
    xs += [x]
    ys += [y]

if len(set(xs))==1 or len(set(ys))==1:
    print "YES"
else:
    print "NO"