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 = int(raw_input())
for i in range(t):
	N = int(raw_input())
	A = []
	for j in range(N):
		A.append(raw_input())
	#A = sorted(A)
	A = set(A)
	A = sorted(A)
	for j in A:
		print j