n = list(input())
flag = False
for i in range(len(n) - 1):
    max_n = max(n[i+1:])
    if n[i] < max_n:
        for j in reversed(range(i + 1, len(n))):
            if n[j] == max_n:
                n[i], n[j] = n[j], n[i]
                break
        break

print("".join(n))