#!/bin/python3
n = int(input())
x = []
y = []
for i in range(n) :
    xi,yi = map(int,input().split())
    x.append(xi)
    y.append(yi)

if len(set(x))==1 :
    print("YES")
elif len(set(y))==1 :
    print("YES")
else :
    print("NO")