#!/bin/python

import sys


n = int(raw_input().strip())
X,Y = map(int,raw_input().strip().split(' '))

vertical = True
horizontal = True

for a0 in xrange(n-1):
    x,y = map(int,raw_input().strip().split(' '))
    
    if vertical or horizontal:
        vertical = x==X
        horizontal = y==Y
    else:
        break
print "YES" if vertical or horizontal else "NO"