#!/bin/python

import sys

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

xx = None
yy = None
x_yes = True
y_yes = True

for point in arr:
    if not xx:
        xx = point[0]
    if not yy:
        yy = point[1]

    if not point[0] == xx:
        x_yes = False
    if not point[1] == yy:
        y_yes = False

if x_yes or y_yes:
    print "YES"
else:
    print "NO"