#!/bin/python3

import sys


n = int(input().strip())
xx = []
yy = []

for _ in range(n):
    x, y = map(int, input().split(' '))
    xx.append(x)
    yy.append(y)
    
if all(xx[0] == x for x in xx[1:]) or all(yy[0] == y for y in yy[1:]):
    print("YES")
else:
    print("NO")