#!/bin/python3

import sys


n = int(input().strip())
points = list()
for a0 in range(n):
    x,y = input().strip().split(' ')
    x,y = [int(x),int(y)]
    points.append((x, y))
if all([points[0][0] == p[0] for p in points]) or all([points[0][1] == p[1] for p in points]):
    print("YES")
else:
    print("NO")