#!/bin/python

import sys


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

if len(set(ax)) == 1 or len(set(ay)) == 1:
    print "YES"
else:
    print "NO"