#!/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, horizontal = True, True
for index, point in enumerate(points):
    if index == 0:
        last_x, last_y = point[0], point[1]
    else:
        if last_x != point[0]:
            horizontal = False
        if last_y != point[1]:
            vertical = False
        if horizontal is False and vertical is False:
            break
            
print('YES' if horizontal or vertical else 'NO')