mod = 998244353


def main():
    import sys
    input = sys.stdin.readline

    N, S = map(int, input().split())

    T = S
    ans = []
    for n in range(N, 0, -1):
        if T >= n:
            T -= n
            ans.append(n)
    print(len(ans))
    ans.reverse()
    print(*ans)


if __name__ == '__main__':
    main()