#!/bin/python

import sys

x_vals = set()
y_vals = set()
n = int(raw_input().strip())
for a0 in xrange(n):
    x,y = raw_input().strip().split(' ')
    
    if x not in x_vals:
      x_vals.add(x)
      
    if y not in y_vals:
      y_vals.add(y)
      
if len(y_vals) == 1 or len(x_vals) == 1:
  print 'YES'
  
else:
  print 'NO'