N,S = map(int,input().split())
cnt = 0
for i in range(N,0,-1):
    if cnt+i<=S:
        cnt += i
        ind = i-1
    else:
        ind = i
        break

if cnt==S:
    A = list(range(ind+1,N+1))
    print(N-ind)
else:
    A = list(range(ind+1,N+1))
    A.insert(0,S-cnt)
    print(N-ind+1)
print(*A)