from sys import stdin, stdout

input = lambda: stdin.readline().rstrip()
write = stdout.write

def main():
    N = list(input())

    l = len(N)
    maxn = '0'
    for i in range(l - 1):
        for j in range(i + 1, l):
            num = N[:]
            num[i], num[j] = num[j], num[i]
            maxn = max(maxn, ''.join(num))
    write(maxn + '\n')

main()