#!/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])
xans = 'YES'
yans = 'YES'
x = -11
y = 11
for i in points:
    if x == -11:
        x = i[0]
    else:
        if i[0] != x:
            xans = 'NO'
    if y == 11:
        y = i[1]
    else:
        if i[1] != y:
            yans = 'NO'
if yans == 'YES' or xans == 'YES':
    print 'YES'
else:
    print 'NO'