#!/bin/python

import sys


n = int(raw_input().strip())
points = []
for a0 in xrange(n):
    x,y = raw_input().strip().split(' ')
    x,y = [int(x),int(y)]
    points.append([x, y])
    
slope = 0
invert = False
b = 0

if (points[1][0] - points[0][0]) == 0:
    invert = True
    
if not invert:
    b =  points[1][1]
else:
    b =  points[1][0]

allIn = True

for i in xrange(n):
    if not invert and points[i][1] != b:
        allIn = False
    elif invert and points[i][0] != b:
        allIn = False
        
if allIn:
    print "YES"
else:
    print "NO"