#!/bin/python

import sys

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

indicator = 0
if pts[0][0] == pts[1][0]:
    for p in xrange(2,n):
        if pts[p - 1][0] != pts[p][0]:
            print "NO"
            indicator = 1
            break
    if indicator == 0:
        print "YES"
elif pts[0][1] == pts[1][1]:
    for p in xrange(2,n):
        if pts[p - 1][1] != pts[p][1]:
            print "NO"
            indicator = 1
            break
    if indicator == 0:
        print "YES"
else:
    print "NO"