---

def solve(n):
    s = str(n)
    arr = []
    for i in range(len(s) - 1):
        val = int(s[i]) * int(s[i + 1])
        arr.append(val)
    arr.sort()
    arr = map(str, arr)
    res = ''.join(arr).lstrip('0')
    return res
n, x = map(int, input().split())
st = 10 ** (len(str(n)) - 1)
en = 10 ** len(str(n))
for i in range(st, en):
    cur = solve(i)
    if len(cur) == x:
        print(cur)
        break