5
10
bb
bb
ab
aa
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10
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ab
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ab
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10
aa
ba
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bb
ab
ab
aa
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bb
10
ab
ab
bb
bb
ab
ba
aa
ba
ab
aa
10
ba
bb
bb
bb
aa
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'''
# Read input from stdin and provide input before running code

name = raw_input('What is your name?\n')
print 'Hi, %s.' % name
'''
for _ in range(input()):
	s = set()
	for _ in range(input()):
		s.add(raw_input())
	s = sorted(list(s))
	for x in s:
		print x