#!/bin/python

import sys

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

horizontal = all(coords[0][0] == c[0] for c in coords)
vertical = all(coords[0][1] == c[1] for c in coords)

print 'YES' if horizontal or vertical else 'NO'