!/bin/python3

import math import os import random import re import sys

if name == 'main': n = int(input()) H = [] V = []

for n_itr in range(n):
    xy = input().split()

    x = int(xy[0])

    y = int(xy[1])

    H.append(xy[0])
    V.append(xy[1])
setH = set(H)
setV = set(V)
if len(setH) == 1 or len(setV) == 1:
    print("YES")
else:
    print("NO")