while True:
    try:
        s = input().split()
        n = int(s[0])
        ls = s[1:-2]
        x = s[-2]
        k = int(s[-1])

        lst = []
        for i in ls:
            if (sorted(i) == sorted(x)) and i != x:
                lst.append(i)
        lst.sort()
        #print(lst)
        print(len(lst))
        if k != 0:
            print(lst[k-1])
    except:
        break