#!/bin/python

import sys


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

if not all(xC[0] == x for x in xC):
    if not all(yC[0] == y for y in yC):
        print "NO"
    else:
        print "YES"
else:
    print "YES"