N = list(map(int, ''.join(input())))
S = sorted(N)
S.reverse()

for i in range(len(N) - 1):
    if N[i] != S[i]:
        k = i
        for j in reversed(range(i + 1, len(N))):
            if N[j] == S[i]:
                k = j
                break

        N[i], N[k] = N[k], N[i]
        break
print(*N, sep='')