class Calc0039
  def initialize(args)
    args = args.map { |l| l.chomp.split(/\s+/) }
    @n = args.shift.first
  end

  def run
    a = @n.split(//)
    a.size.times do |i|
      b = a[i..-1]
      c = b.sort.reverse
      if b.first != c.first
        j = a.rindex(c.first)
        a[i], a[j] = a[j], a[i]
        break
      end
    end
    a.join
  end
end

puts Calc0039.new(STDIN.readlines).run if __FILE__ == $0