#!/bin/python

import sys
from sets import Set

x_list = []
y_list = []
n = int(raw_input().strip())
for _ in xrange(n):
    x,y = raw_input().strip().split(' ')
    x,y = [int(x),int(y)]
    x_list.append(x)
    y_list.append(y)
    
if len(Set(x_list)) == 1 or len(Set(y_list)) == 1:
  print 'YES'
else:
  print 'NO'