#!/bin/python3

import sys

n = int(input().strip())
points=[]
for a0 in range(n):
    x,y = input().strip().split(' ')
    x,y = [int(x),int(y)]
    points.append((x,y))
vertical=True
horizontal=True
for i in range(len(points)-1):
    if points[i][0]==points[i+1][0]:
        vertical &= True
    elif points[i][0]!=points[i+1][0]:
        vertical &= False
    if points[i][1]==points[i+1][1]:
        horizontal &= True
    elif points[i][1]!=points[i+1][1]:
        horizontal &= False

asnwer='YES' if vertical or horizontal else 'NO'
print(asnwer)