let i = require('fs').readFileSync('/dev/stdin', 'utf8').split('\n')[0]
let x = parseInt(i)
i = i.split('')
for (let n = 0; n < i.length - 1; n++) {
  for (let m = n+1; m < i.length; m++) {
    let p = i.concat()
    let t = p[n]
    p[n] = p[m]
    p[m] = t
    let r = parseInt(p.join(''))
    if (x < r) x = r
  }
}
console.log(x)