#!/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))
    
if (all(x == points[0][0] for x, y in points)) or (all(y == points[0][1] for x, y in points)):
    print 'YES'
else:
    print 'NO'