#!/bin/python3

import sys


n = int(input().strip())
xs = set()
ys = set()
result = 'NO'
for a0 in range(n):
    x,y = input().strip().split(' ')
    xs.add(x)
    ys.add(y)
if len(xs) == 1 or len(ys) == 1:
    result = 'YES'
print(result)