n = gets.to_i
A = gets.split.map(&:to_i)

(n-1).times do |i|
  a = A.dup
  a[i],a[i+1] = a[i+1],a[i]
  (n-1).times do |j|
    if a[j] == a[j+1]
      puts "Yes"
      exit
    end
  end
end
puts "No"