from fractions import gcd
from heapq import*
import math
from collections import defaultdict, Counter
import sys
sys.setrecursionlimit(10 ** 7)
MOD = 10 ** 9 + 7


def main():
    n = int(input())
    sn = list(str(n))
    change = -1
    for i in range(1, len(sn)):
        base = int(sn[i-1])
        for j in range(len(sn)-1, i-2, -1):
            if int(sn[j]) > base:
                change = j
                base = int(sn[j])
        if change != -1:
            break

    if change == -1:
        print(n)
        exit()

    sn[i-1], sn[change] = sn[change], sn[i-1]
    print(max(n, int("".join(map(str, sn)))))


if __name__ == '__main__':
    main()