#!/bin/python

import sys


n = int(raw_input().strip())
x,y = raw_input().strip().split(' ')
x,y = [int(x),int(y)]

xaxis, yaxis = x, y
xline, yline = True, True
for a0 in xrange(1, n):
    x,y = raw_input().strip().split(' ')
    x,y = [int(x),int(y)]
    if x != xaxis:
        xline = False
    if y != yaxis:
        yline = False
        
if xline or yline:
    print "YES"
else:
    print "NO"