require "set"

S = gets.chomp.chars

st = Set.new

S.size.times do |i|
  i.upto(S.size - 1) do |j|
    n = Marshal.load(Marshal.dump(S))
    n[i], n[j] = n[j], n[i]
    st.add(n.join.to_i)
  end
end

puts st.max