#!/bin/python

import sys


n = int(raw_input().strip())
l=[] 
r=[]
for a0 in xrange(n):
    x,y = map(int,raw_input().strip().split(' '))
    l.append(x)
    r.append(x)
if l.count(0)==n or r.count(0)==n:
    print "YES"
else:
    flag=0
    for j in range(-10,11):
        if l.count(j)==n or r.count(j)==n:
            flag=1
            print "YES"
            break
    if flag==0:
        print "NO"