#include <bits/stdc++.h>
using namespace std;
using lint = long long;
template<class T = int> using V = vector<T>;
template<class T = int> using VV = V< V<T> >;

int main() {
  cin.tie(nullptr); ios::sync_with_stdio(false);
  int n, x; cin >> n >> x;
  if (n == 2) {
    if (x == 1) {
      cout << 2 << '\n';
      cout << 3 << '\n';
    } else {
      cout << 1 << '\n';
      cout << (x ^ 1) << '\n';
    }
    return 0;
  }

  V<> res;
  auto add = [&](int l, int r) -> void {
    for (int i = l; i < r; ++i) {
      res.push_back(i);
    }
  };

  assert(n % 4 <= 1);
  if (n % 4 == 0) {
    if (x < 4) {
      assert(false);
      res.push_back(16 | x);
      res.push_back(20);
      res.push_back(24);
      res.push_back(28);
    } else {
      add(1, 4);
      int m = n / 4 - 1;
      for (int i = 4; m; i += 4, --m) {
        if (i <= x and x < i + 4) continue;
        add(i, i + 4);
      }
      res.push_back(x);
    }
  } else if (n % 4 == 1) {
    int m = n / 4;
    for (int i = 4; m; i += 4, --m) {
      if (i <= x and x < i + 4) continue;
      add(i, i + 4);
    }
    res.push_back(x);
  } else if (n % 4 == 2) {
    for (int i = x / 4 * 4; i < x / 4 * 4 + 4; ++i) if (i != x) {
      res.push_back(i);
    }
    add(1, 4);
    int m = n / 4;
    for (int i = 4; m; i += 4, --m) {
      if (i <= x and x < i + 4) continue;
      add(i, i + 4);
    }
  } else {
    for (int i = x / 4 * 4; i < x / 4 * 4 + 4; ++i) if (i != x) {
      res.push_back(i);
    }
    int m = n / 4;
    for (int i = 4; m; i += 4, --m) {
      if (i <= x and x < i + 4) continue;
      add(i, i + 4);
    }
  }

  for (int e : res) {
    cout << e << '\n';
  }
}