#!/bin/python3

import sys


n = int(input().strip())
x1,y1 = -11,-11
count1 = 0
count2 = 0
for a0 in range(n):
    x,y = input().strip().split(' ')
    x,y = [int(x),int(y)]
    
    if(x1== -11 and y1 == -11):
        x1 = x
        y1 = y
        count1+=1
        count2+=1
    else:
        if(x1==x):
            count1+=1
        if(y1==y):
            count2+=1
            
if(count1==n or count2==n):
    print("YES")
else:
    print("NO")