#!/bin/python

import sys

xl,yl = [],[]
n = int(raw_input().strip())
for i in xrange(n):
    x,y = list(map(int,raw_input().strip('').split()))
    x,y = xl.append(x),yl.append(y)
    
if len(set(xl)) == 1 or len(set(yl)) == 1:
    print "YES"
else:
    print "NO"