import sys
if sys.platform =='ios':
	import clipboard
	a=clipboard.get()
	a = a.split('\n')
	text = '\n'.join(a)
	with open('input_file.txt','w') as f:
		f.write(text)
	sys.stdin = open('input_file.txt')
	
ans = []
n,s = map(int,input().split())
for i in range(n,0,-1):
	
	if s-i >= 0:
		s -= i
		ans.append(i)
	else:
		continue
	if s == 0:
		break
print(ans)
if s != 0:
	exit(print(-1))		
print(max(ans))
print(*ans[::-1])