5
10
bb
bb
ab
aa
bb
bb
ba
aa
bb
ab
10
bb
ab
ba
ab
ba
ba
ab
ba
ba
ba
10
aa
ba
ba
ba
bb
ab
ab
aa
bb
bb
10
ab
ab
bb
bb
ab
ba
aa
ba
ab
aa
10
ba
bb
bb
bb
aa
ba
ba
ba
bb
bb
aa
ab
ba
bb
ab
ba
bb
aa
ab
ba
bb
aa
ab
ba
bb
aa
ba
bb

t = input()

for i in range(t):
    n = input()
    dic= {}
    for j in range(n):
        st = raw_input()
        if st not in dic:
            dic[st] = ""

    nms = dic.keys()
    nms.sort()
    for nm in nms:
        print(nm)