n = gets.chomp.chars

p [n.join.to_i].tap{|cands|
  (0...n.size).each do |i|
    (i.succ...n.size).each do |j|
      n.dup.tap do |m|
        if m[i] < m[j]
          m[i], m[j] = m[j], m[i]
          cands << m.join.to_i
        end
      end
    end
  end
}.max