py_v1_t2

import copy

n = input()
state = input()

if state == '0':
    tc = 1
    while True:
        ptrn = '1' * len(n)

        if int(n) > int(ptrn)*tc:
            tc += 1
        else:
            print(int(ptrn)*tc)
            break

else:
    dgs = set([x for x in n])
    skipping_1 = False

    if len(dgs) in (1, 2):
        print(n)
        skipping_1 = True

    if not skipping_1:
        n = [int(x) for x in n]
        result = copy.deepcopy(n)

        diffs_cnt = 0
        mx_char = n[0]
        mx_char_idx = 0
        c_pos = 1

        if n[0] != n[1]:
            diffs_cnt += 1

        px_fill = -1
        change_pos = -1
        for I in range(0, len(n)):
            if n[I] > mx_char:
                px_fill = min(n[:I]) # n[I]
                change_pos = I
                break

            if n[I] < mx_char:
                change_pos = I
                px_fill = mx_char
                break

        # print(px_fill, change_pos)
#
        diffs_before = len(set([x for x in n[:change_pos]]))

        for O in range(len(n) - 1, diffs_before, -1):
            if result[O - 1] < result[O]:
                result[O - 1] += 1

        # print(n)

        cma_diffs = 0
        cmp_sym = n[0]

        r1 = ''
        r2 = ''
        for B in range(len(n)):
            if result[B] != cmp_sym:
                cma_diffs += 1
                cmp_sym = n[B]

            if cma_diffs == 2 or (B + 1 == len(n)):
                gfs = None

                # lst_p = n[-1]
                # lst_p_i = len(n) - 1
                pfi = False
                answ = ''
                for ci in range(len(n) - 1, 0, -1):
                    if n[ci] < n[ci-1] and (len(set(n[:ci])) == 2):
                        cr = result[ci - 1]
                        while result[ci] == cr:
                            ci -= 1
                        # n[ci] = max(result[:ci])
                        n[ci] = result[ci]
                        # print(''.join(chr(x + ord('0')) for x in n))
                        answ = ''.join(chr(x + ord('0')) for x in n)
                        pfi = True

                if not pfi:
                    # print(''.join(chr(ord('0') + x) for x in n[:B]) + chr(min(n[:B]) + ord('0')) * (len(n) - B))
                    # r1 = ''.join(chr(ord('0') + x) for x in n[:B]) + chr(min(n[:B]) + ord('0')) * (len(n) - B)
                    answ = ''.join(chr(ord('0') + x) for x in n[:B]) + chr(min(n[:B]) + ord('0')) * (len(n) - B)
                    # print(r1)
                    # break
                print(answ)