#!/bin/python

from collections import Counter


n = int(raw_input().strip())
ip=[]
for a0 in xrange(n):
    x,y = map(int,raw_input().strip().split(' '))
    ip.append(list([x,y]))
ipx=map(lambda x:x[0],ip)
ipy=map(lambda x:x[1],ip)
x=len( Counter(ipx).values())
y=len( Counter(ipy).values())
if x==1 or y==1:
    print "YES"
else:
    print "NO"