#!/bin/python3

import sys

def find(l):
    for i in range(len(l)-1):
        if l[i] != l[i+1]:
            return False
    return True
   


n = int(input().strip())
l1 = []
l2 = []
for a0 in range(n):
    x,y = input().strip().split(' ')
    x,y = [int(x),int(y)]
    l1.append(x)
    l2.append(y)
    

if find(l1) or find(l2):
    print ("YES")
else: print ("NO")