while True:
try:
s1=input().split()
n=int(s1[0])#单词个数
s2=s1[1:n+1]#n个单词
ss=s1[n+1]#待查找的单词x
k=int(s1[-1])#数字k
brs=[]
for s in s2:
if len(s)==len(ss) and ss!=s and sorted(ss)==sorted(s):
brs.append(s)
brs=sorted(brs)#经字典序排列
print(len(brs))
print(brs[k-1])
except:
break