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

testcases=int(raw_input())
word=[]
for i in range(testcases):
    n=int(raw_input())

    for j in range(n):
        value=raw_input()
        word.append(value)
    
    result=set(word)
    result=sorted(result)
    for k in result:
        print (k)
    
    del word[:]