N = [int(x) for x in list(input())]

for idx, num in enumerate(N[:-1]):
    m = max(N[idx+1:])
    if m <= num:
        continue
    else:
        i = N[::-1].index(m)
        f = N[idx]
        N = N[::-1]
        N[i] = f
        N = N[::-1]
        N[idx] = m
        print(''.join(map(str, N)))
        break
else:
    print(''.join(map(str, N)))