fp = input().split()
wordList = []
result = []
for i in range(int(fp[0])):
    wordList.append(fp[i + 1])
word = fp[-2]
num = int(fp[-1])
for j in wordList:
    if j != word:
        if "".join(sorted(j)) == "".join(sorted(word)):
            result.append(j)
result.sort()
print(len(result))
if len(result) > num:
    print(result[num - 1])