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

def setToList(s):
    l=list(s)
    l.sort()
    return l

def printList(l):
    for i in l:
        print i

t=int(raw_input())
for i in range(t):
    n=int(raw_input())
    s=set()
    for j in range(n):
        s.add(raw_input())
    printList(setToList(s))