#!/bin/python3

import sys


n = int(input().strip())
points = []
for a0 in range(n):
    x,y = input().strip().split(' ')
    points.append((int(x),int(y)))
hor = True
ver = True
x0, y0 = points[0]
for x, y in points[1:]:
    if ver and x != x0:
        ver = False
    if hor and y != y0:
        hor = False
    if not (ver or hor):
        break
print("YES" if ver or hor else "NO")