#!/bin/python

import sys


n = int(raw_input().strip())
x= [0]*n
y= [0]*n
for a0 in xrange(n):
    x[a0],y[a0] = raw_input().strip().split(' ')
    x[a0],y[a0] = [int(x[a0]),int(y[a0])]
if sum([1 for i in x if i!=x[0]])==0 or sum([1 for i in y if i!=y[0]])==0 :
    print 'YES'
else:
    print 'NO'