#!/bin/ruby

n = gets.strip.to_i
array = []
for a0 in (0..n-1)
  var = []
  input = gets.chomp.split(" ").map {|x| x.to_i}
  var.push(input[0])
  var.push(input[1])
  array.push(var)
end

lastX = array[0][0]
lastY = array[0][1]

iguaisX = 0
iguaisY = 0
array.each do |value|
  iguaisX += 1 if value[0] == lastX
  iguaisY += 1 if value[1] == lastY
end

if (iguaisX == array.length || iguaisY == array.length)
  result = "YES"
else
  result = "NO"
end

puts result