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(input())
while t>0:
	t=t-1
	a = list()
	n = int(input())
	for i in range(0,n):
		a.append(raw_input())
	a = sorted(a)
	tmp=a[0]
	print tmp
	for i in range(1,n):
		if tmp!=a[i]:
			print a[i]
			tmp=a[i]