import strutils, algorithm

let N = stdin.readLine
var arr = @[N.parseInt]


for i in 0 ..< N.len:
  for j in (i + 1) ..< N.len:
    var ch_arr = N.reversed.reversed
    swap(ch_arr[i], ch_arr[j])
    let v = ch_arr.join.parseInt
    if v > arr.max:
      arr.add v

echo arr.max