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

test=int(raw_input())
while test:
	n=int(raw_input())
	t=[]
	t2=[]
	for i in range(1,n+1):
		t.append(raw_input())	
	t=list(set(t))	
	t.sort()
	for i in range(0,len(t)):
	  print t[i]
	test=test-1