import math
import sys
def S(): return sys.stdin.readline().rstrip()
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int, sys.stdin.readline().rstrip().split())
def LI(): return list(map(int, sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())

s = S()
n = len(s)

m = int(s)

for i in range(n):
    for j in range(i+1, n):
        n_list = list(s)
        n_list[i], n_list[j] = n_list[j], n_list[i]
        m = max(m, int("".join(n_list)))

print(m)