N = int(input())
listN = list(str(N))
maxs = [i for i,x in enumerate(listN) if x == max(listN)]
id = maxs[-1]
for i in range(id):
    if listN[i] < listN[id]:
        listN[i],listN[id] = listN[id],listN[i]
        break
print(int("".join(map(str,listN))))