def 🎍(a,b,c)
    a != c && ((a < b && b > c) || (a > b && b < c))
end

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

not_kado_idxs = arr.each_cons(3).each_with_index.map{|a,i| 🎍(*a) ? nil : i}.compact

if not_kado_idxs.size > 20
    puts 'No'
end

ok = false
n.times do |i|
    not_kado_idxs.each do |ji|
        3.times do |jj|
            j = ji+jj
            next if i == j
            arr[i], arr[j] = arr[j], arr[i]
            ok ||= arr.each_cons(3).all?{|a| 🎍(*a)}
            arr[i], arr[j] = arr[j], arr[i]
        end
    end
end

puts ok ? 'Yes' : 'No'