N = int(input())

ls = [-1] * 10
rs = [-1] * 10
for i, d in enumerate(map(int, str(N))):
    if ls[d] == -1:
        ls[d] = i

    rs[d] = i


cands = []
for i in range(1, 10):  # 入れ替え要素(左)
    if ls[i] == -1: continue
    for j in reversed(range(i+1, 10)):  # 入れ替え要素(右)
        if rs[j] == -1: continue
        if ls[i] >= rs[j]: continue  # 入れ替えると小さくなる

        cands.append([(ls[i], i), (-rs[j], j)])

if not cands:
    print(N)
    exit()

a, b = min(cands)
s = list(str(N))

ai, bi = a[0], -b[0]
s[ai], s[bi] = s[bi], s[ai]
ans = ''.join(s)
print(ans)