#!/bin/python

import sys


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

if len(set(X))==1 or len(set(Y))==1:
    print 'YES'
else: print 'NO'