5
10
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10
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10
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10
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aa
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ab
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10
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bb
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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
'''
tc = input()
while tc > 0:
	dict ={}
	n = input()
	for _ in range(n):
		str = raw_input()
		dict[str]=1
	for na in sorted(dict.keys()):
		print na
	
	
	tc -=1