1728.commonPermutation.py

def common(a, b):
	out = []
	for i in a:
		try:
			b.remove(i)
			out.append(i)
		except ValueError:
			pass
	return sorted(out)
while True:
	try:
		a = raw_input()
		b = raw_input()
	except EOFError:
		break
	print ''.join(common(list(a), list(b)))