N = list(raw_input())
mx = max(N)
index = N.index(mx)

afterForMaxId = [len(N)-1] * len(N)

for i in xrange(len(N) - 2, -1, -1):
    id = afterForMaxId[i + 1]
    if N[id] < N[i]:
        id = i
    afterForMaxId[i] = id

for i in xrange(len(N)):
    id = afterForMaxId[i]
    if N[i] < N[id]:
        tmp = N[i]
        N[i] = N[id]
        N[id] = tmp
        break
print "".join(N)