#!/bin/python3

import sys


n = int(input().strip())
countx = {}
county = {}
for a0 in range(n):
    x,y = input().strip().split(' ')
    x,y = [int(x),int(y)]
    countx[x] = 1
    county[y] = 1
if len(countx) > 1 and len(county) > 1:
    print("NO")
else:
    print("YES")