#!/bin/python

import sys

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

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