#!/bin/python

import sys


n = int(raw_input().strip())
li=[]
for a0 in xrange(n):
    x,y = raw_input().strip().split(' ')
    li.append([int(x),int(y)])
if li[1][0]-li[0][0]==0:
    line=True
elif li[1][1]-li[0][1]==0:
    line=False
else:
    print "NO"
    sys.exit(0)
for x in range(0,n-1):
    if line:
        if li[x+1][0]-li[x][0]!=0:
            print "NO"
            sys.exit(0)
    else:
        if li[x+1][1]-li[x][1]!=0:
            print "NO"
            sys.exit(0)
print 'YES'