X = gets.to_i
D = X.to_s.size

$values = []

def dfs(stack, depth, counter)
  if depth == D
    $values << stack.join.to_i
    return
  end

  9.downto(0) do |n|
    return if $values.size >= 2

    next if depth == 0 && n == 0
    next if counter[n] == 0

    counter[n] -= 1
    stack << n

    dfs(stack, depth + 1, counter)

    counter[n] += 1
    stack.pop
  end
end

counter = Hash.new(0)

X.digits.each do |x|
  counter[x] += 1
end

dfs([], 0, counter)

if $values.size >= 2
  puts $values.last
else
  puts -1
end