#!/bin/python3

import sys

x_line = True
y_line = True

x_prev = 0
y_prev = 0
n = int(input().strip())
for a0 in range(n):
    x,y = input().strip().split(' ')
    x,y = [int(x),int(y)]
    if a0 != 0:
        if x_line and x_prev != x:
            x_line = False
        if y_line and y_prev != y:
            y_line = False
    x_prev,y_prev = x,y
print('YES' if x_line or y_line else 'NO')