#!/bin/python3

import sys


n = int(input().strip())
s_x = 1 
s_y = 1
li_x = []
li_y = []
for a0 in range(n):
    x,y = input().strip().split(' ')
    x,y = [int(x),int(y)]
    li_x.append(x)
    li_y.append(y)
for i in range(1,n):
    if li_x[i] != li_x[i-1]:
        s_x = 0
    if li_y[i] != li_y[i-1]:
        s_y = 0
if s_y == 1 or s_x == 1:
    print("YES")
else:
    print("NO")