# -*- coding: utf-8 -*-

N = input()
n = list(map(int, list(N)))
m = list(map(int, list(N)))

m.sort()
m.reverse()
start = end = -1
for i in range(len(m)):
    if m[i]!=n[i]:
        start = i
        break

if start != -1:
    for i in range(len(n)-1, -1, -1):
        if m[start] == n[i]:
            end = i
            break

    temp = n[start]
    n[start] = n[end]
    n[end] = temp

    answer = ''
    for i in n:
        answer += str(i)

    print(answer)
else:
    print(N)