#!/bin/python

import sys

xl = []
yl = []
n = int(raw_input().strip())
for a0 in xrange(n):
    x,y = raw_input().strip().split(' ')
    x,y = [int(x),int(y)]
    xl.append(x)
    yl.append(y)
xs = 1 if max(xl) == min(xl) else 0
ys = 1 if max(yl) == min(yl) else 0
print 'YES' if xs == 1 or ys ==1 else 'NO'