import sys
nn = 1
or_list = []
for i in sys.stdin:
if nn%2 == 0:
or_list.append(i.strip())
nn += 1
mm = 0
while True:
try:
all_list = or_list[mm].split(" ") + or_list[mm+1].split(" ")
all_set =list(set(map(int, all_list)))
all_set.sort()
print("".join(map(str,all_set)))
mm += 2
except Exception:
break