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

__author__ = 'srikanth'
for _ in range(int(raw_input())):
    A = {}
    for q in range(int(raw_input())):
            A.__setitem__(raw_input(), 1)
    for i in sorted(A.keys()):
        print(i)