while True:
	try:  
		n = int(raw_input())
		if n == 0:
			break;
		li = raw_input().strip().split();
		
		lis = []
		for i in range(n):
			lia = list(li[i]);
			lia.sort();
			lis.append(int("".join(lia)));

		s = 0
		lic = []
		lid = map(int,li)
		for i in range(n):
			if(lis.count(lis[i]) == 1):
				lic.append(lid[i])
				s = 1;
		
		if len(lic) == 0:
			print "None"
		else:
			lic.sort()
			for v in lic:
				print v,
			print

	except EOFError:  
		break