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

noftestcases = int(raw_input())
li = []
final = []
for i in range(0,noftestcases):
    n = int(raw_input())
    for j in range(0,n):
        temp = str(raw_input())
        li.append(temp)
    final.append(sorted(list(set(li))))
    li =[]
for i in range(0,len(final)):
	for j in range(0,len(final[i])):
		print(final[i][j])