#!/bin/python

import sys

def same_number(numbers):
    return all(x == numbers[0] for x in numbers)


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

if same_number(x_coord) or same_number(y_coord):
    print 'YES'
else:
    print 'NO'