#!/bin/python

import sys


n = int(raw_input().strip())
x_set = set()
y_set = set()
for a0 in xrange(n):
    x,y = raw_input().strip().split(' ')
    x,y = [int(x),int(y)]
    x_set.add(x)
    y_set.add(y)
if len(x_set) > 1:
    if len(y_set) > 1:
        print "NO"
    else:
        print "YES"
else:
    print "YES"