public static void main(String[] args) {
FastScanner in = new FastScanner(System.in);
int sum = in.nextInt();
int limit = in.nextInt();
int cnt = 0;
StringBuilder sb = new StringBuilder();
Point[] points = new Point[limit + 1];
points[0] = new Point(0, 0);
for (int i = 1; i <= limit; i++) points[i] = new Point(i, lb(i));
Arrays.sort(
points,
new Comparator<Point>() {
public int compare(Point a, Point b) {
return a.y - b.y;
}
});
// System.out.println(Arrays.toString(points));
for (int i = limit; i >= 1; i--) {
if (sum >= points[i].y) {
sum -= points[i].y;
sb.append(" ");
sb.append(points[i].x);
cnt++;
}
}
if (sum == 0) {
System.out.println(cnt);
System.out.println(sb.toString().trim());
} else {
System.out.println(-1);
}
}
public void solve() throws IOException {
int n = in.nextInt();
int m = in.nextInt();
graph = new ArrayList[n + 1];
color = new int[n + 1];
Arrays.fill(color, 0);
for (int i = 0; i < m; i++) {
int from = in.nextInt();
int to = in.nextInt();
if (graph[from] == null) {
graph[from] = new ArrayList<Integer>();
}
graph[from].add(to);
}
topSort();
if (hasCycle) {
out.print(-1);
return;
}
for (Integer anAnswer : answer) {
out.printf("%d ", anAnswer);
}
}
protected static void calcTransferCombinations() throws IOException {
FastScanner in = new FastScanner(System.in);
PrintWriter out = new PrintWriter(System.out);
final int PRISONERS_NUMBER = in.nextInt();
final int MAX_AGGRESSION = in.nextInt();
final int RANK_LENGTH = in.nextInt();
int combinations = PRISONERS_NUMBER - RANK_LENGTH + 1;
int distanceToLastDangerous = RANK_LENGTH;
int itr = 1;
while (itr <= PRISONERS_NUMBER) {
int aggression = in.nextInt();
if (aggression > MAX_AGGRESSION) {
if (PRISONERS_NUMBER - itr < RANK_LENGTH) {
combinations -= Math.min(PRISONERS_NUMBER - itr + 1, distanceToLastDangerous);
break;
}
int left = min(itr, RANK_LENGTH, distanceToLastDangerous);
combinations -= left;
distanceToLastDangerous = 0;
}
distanceToLastDangerous++;
itr++;
}
out.print(combinations);
out.flush();
}
public static void main(String[] args) {
FastScanner in = new FastScanner(System.in);
int n = in.nextInt();
int[] s = new int[n + 5];
int[] s2 = new int[n + 5];
for (int i = 1; i <= n; i++) {
s[i] = in.nextInt();
s2[n - i + 1] = s[i];
}
int[] stack = new int[n + 5];
int size = 0;
int answer = 0;
for (int i = 1; i <= n; i++) {
while (size > 0 && stack[size - 1] < s[i]) size--;
stack[size++] = s[i];
if (size >= 2) answer = Math.max(answer, stack[size - 1] ^ stack[size - 2]);
}
size = 0;
for (int i = 1; i <= n; i++) {
while (size > 0 && stack[size - 1] < s2[i]) size--;
stack[size++] = s2[i];
if (size >= 2) answer = Math.max(answer, stack[size - 1] ^ stack[size - 2]);
}
System.out.println(answer);
}
public void solve() throws IOException {
/* MAIN CODE GOES HERE!!! */
MyQueueOnMyLinkedList q = new MyQueueOnMyLinkedList();
int n = in.nextInt();
for (int i = 0; i < n; i++) {
String s = in.next();
if (s.charAt(0) == '-') {
out.println(q.pop());
} else if (s.charAt(0) == '+') {
q.push(in.nextInt());
}
}
}
private void scanData() {
int citiesNumber = scanner.nextInt();
maxPossibleCapacity = 0;
adjacencyMatrix = new int[citiesNumber][citiesNumber];
for (int startCity = 0; startCity < citiesNumber; startCity++) {
for (int destinationCity = 0; destinationCity < citiesNumber; destinationCity++) {
int nextCapacity = scanner.nextInt();
adjacencyMatrix[startCity][destinationCity] = nextCapacity;
if (nextCapacity > maxPossibleCapacity) {
maxPossibleCapacity = nextCapacity;
}
}
}
graph = new CitiesFuelGraph(adjacencyMatrix);
}
public static void main(String[] args) {
FastScanner scanner = new FastScanner(System.in);
int n = scanner.nextInt();
int m = scanner.nextInt();
assert 1 <= n && n <= 1e6 : "out of range, n: " + n;
assert 2 <= m && m <= 1e3 : "out of range, m: " + m;
int[] A = new int[n];
for (int i = 0; i < A.length; i++) {
A[i] = scanner.nextInt();
assert 0 <= A[i] && A[i] <= 1e9 : "out of range, A[i]: " + A[i];
if (A[i] == 0) {
System.out.println("YES");
return;
}
}
Bravo o = new Bravo(n, m, A);
System.out.println((o.solve()) ? "YES" : "NO");
}
int nextInt() {
return sc.nextInt();
}