#!/bin/python

isV,isH = True,True

n = int(raw_input().strip())
xb,yb = 0,0
for i in xrange(n):
    x,y = map(int,raw_input().strip().split(' '))
    if i>0 and isV:
        isV = xb==x
    if i>0 and isH:
        isH = yb==y
    xb,yb = x,y
    
print "{}".format("YES" if (isV or isH) else "NO")