#!/bin/python3

import sys

is_x = True
is_y = True
prev_x = None
prev_y = None

n = int(input().strip())
prev_x, prev_y = input().strip().split(' ')
prev_x, prev_y = [int(prev_x), int(prev_y)]
for a0 in range(1, n):
    x,y = input().strip().split(' ')
    x,y = [int(x),int(y)]
    
    is_x = ((x == prev_x) and is_x) and True or False
    is_y = ((y == prev_y) and is_y) and True or False
    
    prev_x = x
    prev_y = y
    
msg = (is_x or is_y) and 'YES' or 'NO'
print(msg)