#!/bin/python3

import sys


n = int(input().strip())
vert = True
horz = True
points = []
for a0 in range(n):
    x,y = input().strip().split(' ')
    x,y = [int(x),int(y)]
    points.append((x, y))

h = points[0][0]
v = points[0][1]
for i in range(1, len(points)):
    point = points[i]
    if point[0] != h:
        horz = False
    if point[1] != v:
        vert = False

if not horz and not vert:
    print("NO")
else:
    print("YES")