#!/bin/ruby

n = gets.strip.to_i
points = []
for a0 in (0..n-1)
    x,y = gets.strip.split(' ')
    points << [x.to_i,y.to_i]
end

if points.map {|p| p[0]}.uniq.count == 1 || points.map {|p| p[1]}.uniq.count == 1
    puts "YES"
else
puts "NO"
end