#!/bin/python3

import sys


n = int(input().strip())
xx = []
yy = []
for a0 in range(n):
    x,y = input().strip().split(' ')
    x,y = [int(x),int(y)]
    xx.append(x)
    yy.append(y)
fx=1
fy=1
for i in range(1,len(xx)):
    if xx[i-1]!=xx[i]:
        fx=0
        break
for i in range(1,len(yy)):
    if yy[i-1]!=yy[i]:
        fy=0
        break
if fx or fy:
    print("YES")
else:
    print ("NO")