题解 | #查找兄弟单词#

words = input().split()
n = int(words.pop(0))
index = int(words.pop()) - 1
brother = words.pop()
count = 0
ret = []
for word in words:
    if len(word) != len(brother):
        continue
    is_brother = True
    for c in brother:
        if brother.count(c) != word.count(c):
            is_brother = False
            break
    if is_brother and word != brother:
        ret.append(word)
ret.sort()
print(ret.__len__())
if index < ret.__len__():
    print(ret[index])