import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

import itertools

N = [str(x - ord('0')) for x in read().rstrip()]

to_int = lambda x: int(''.join(x))

cand = [to_int(N)]

for i,j in itertools.combinations(range(len(N)),2):
    N[i],N[j] = N[j],N[i]
    cand.append(to_int(N))
    N[i],N[j] = N[j],N[i]

answer = max(cand)
print(answer)