#!/bin/python

import sys
n = input()
xp = 0
yp = 0
xs = 0
ys = 0
ctr = 0
for a0 in xrange(n):
    x,y = raw_input().strip().split(' ')    
    x,y = [int(x),int(y)]
    if a0 == 0:
        xp = x
        yp = y
    if not(xp == x):
        xs = 1
    if not(yp == y):
        ys = 1
    

if ys and xs:
    print 'NO'
else:
    print 'YES'