#!/bin/python

import sys

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

is_vertical = reduce(lambda x, y: x and y == xs[0], xs, True)
is_horizontal = reduce(lambda x, y: x and y == ys[0], ys, True)

print 'YES' if is_vertical or is_horizontal else 'NO'