#!/bin/python3

import sys
from collections import Counter

n = int(input().strip())
cx, cy = Counter(), Counter()
for a0 in range(n):
    x,y = input().strip().split(' ')
    x,y = [int(x),int(y)]
    cx[x] += 1
    cy[y] += 1

if len(cx) == 1 or len(cy) ==1:
    print('YES')
else:
    print('NO')