#!/bin/python3

import sys

def same_line(lst):
    xval = lst[0][0]
    yval = lst[0][1]
    xboo = True
    yboo = True
    for pt in lst:
        xboo = xboo and pt[0] == xval
        yboo = yboo and pt[1] == yval
    return xboo or yboo

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

if same_line(lst):
    print("YES")
else:
    print("NO")