#!/bin/python3

import sys


n = int(input().strip())
vx = []
vy = []
for a0 in range(n):
    x,y = input().strip().split(' ')
    x,y = [int(x),int(y)]
    vx.append(x)
    vy.append(y)
resx = resy = "YES"
for i in range(1,n):
    if vx[i-1] != vx[i]:
        resx = "NO"
    if vy[i-1] != vy[i]:
        resy = "NO"
if  resx == "YES" or resy == "YES":
    print("YES")
else :
    print("NO")