#!/bin/python

import sys
def checkEqual2(iterator):
    return len(set(iterator))
lstx=list()
lsty=list()
n = int(raw_input().strip())
for a0 in xrange(n):
    x,y = raw_input().strip().split(' ')
    x,y = [int(x),int(y)]
    lstx.append(x)
    lsty.append(y)
if min(lstx)==max(lstx):
    print "YES"
else:
    if min(lsty)==max(lsty):
        print "YES"
    else:
        print "NO"