#!/bin/python

import sys


n = int(raw_input().strip())
allpoints = list()
x_set = set()
y_set = set()
for a0 in xrange(n):
    x,y = raw_input().strip().split(' ')
    x,y = [int(x),int(y)]
    x_set.add(x)
    y_set.add(y)

if (len(x_set) == 1) or (len(y_set) == 1): 
    print 'YES'
else: 
    print 'NO'