#!/bin/python

import sys
xAx,yAx=[],[]
for _ in xrange(input()):
    a,b = map(int,raw_input().split())
    xAx.append(a)
    yAx.append(b)
    
if(len(set(xAx))==1 or len(set(yAx))==1):
    print "YES"
else:
    print "NO"