#include <bits/stdc++.h>
using namespace std;
const int N = 1000001;
int n, kt[N], a[N], cnt, x[N];
long long k, s;
long long cal(int i) {
  long long res = i;
  return res * (res + 1) / 2;
}
int main() {
  scanf("%d%lld", &n, &k);
  if (k < cal(n)) {
    printf("-1");
    return 0;
  }
  for (int i = n; i > 0; i--) {
    int h = n - (n - i) / 2;
    if (k - h < cal(i - 1)) h = k - cal(i - 1);
    k -= h;
    kt[h]++;
    if (kt[h] == 2) a[++cnt] = h;
  }
  for (int i = 1; i <= n; i++) s += kt[i] * i;
  printf("%lld\n", s);
  for (int i = 1; i <= n; i++) {
    if (kt[i] == 1)
      x[i] = i;
    else if (kt[i] == 0) {
      x[a[cnt]] = i;
      x[i] = a[cnt];
      cnt--;
    }
  }
  for (int i = 1; i <= n; i++) printf("%d ", i);
  printf("\n");
  for (int i = 1; i <= n; i++) printf("%d ", x[i]);
  return 0;
}
