def main():
    S = input()
    rev = sorted(S, reverse=True)
    a = b = 0
    for i in range(len(S)):
        if S[i] != rev[i]:
            a, b = i, S.rfind(rev[i])
            break
    ans = list(S)
    ans[a], ans[b] = ans[b], ans[a]
    print(''.join(ans))

main()