题解 | #查找兄弟单词#

from itertools import permutations
while True:
    try:
        num = input().split(' ')
        n = int(num[0])
        nums = num[1:n+1]
        x = list(num[n+1])
        k = int(num[-1])
        result = []
        for b in list(set(permutations(x))):
            for i in range(len(nums)):
                c = "".join(b)
                if c == nums[i] and c != "".join(x):
                    result.append(c)
        result.sort()
        print(len(result))
        if k < len(result):
            print(result[k-1])
    except:
        break