#!/usr/bin/env python3
#fileencoding: utf-8

N = list(input())
ma = -1
for i in range(len(N)-1):
    for j in range(i,len(N)):
        N[i],N[j] = N[j], N[i]
        tmp = int("".join(N))
        if tmp > ma:
            ma = tmp
        N[i],N[j] = N[j], N[i]

print(ma)