#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T>
ostream_iterator<T> oit(const string &s = " "){ return ostream_iterator<T>(cout,s.c_str()); }
inline auto rep(int l, int r) { return views::iota(min(l, r), r); }
inline auto rep(int n) { return rep(0, n); }
inline auto rep1(int l, int r) { return rep(l, r + 1); }
inline auto rep1(int n) { return rep(1, n + 1); }
inline auto per(int l, int r) { return rep(l, r) | views::reverse; }
inline auto per(int n) { return per(0, n); }
inline auto per1(int l, int r) { return per(l, r + 1); }
inline auto per1(int n) { return per(1, n + 1); }
#define A(a) begin(a),end(a)
inline auto len = ranges::ssize;

struct chash {
    static uint64_t splitmix64(uint64_t x) {
        // http://xorshift.di.unimi.it/splitmix64.c
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};
template<typename T, typename U> using pb_map = gp_hash_table<T, U, chash>;
template<typename T> using pb_set = gp_hash_table<T, null_type, chash>;
#define K first
#define V second

using ll = long long;
using ld = long double;

using vi = vector<int>;
using vii = vector<vector<int>>;
typedef vector<ll> vll;
using pll = pair<ll,ll>;
using pii = pair<int,int>;

void run()
{
    enum Day{
        open,close
    };
    ll n,R; cin >> n >> R;

    vll ans;
    vll v(n);for(ll &x : v) cin >> x;
    // ranges::sort(v);
    // auto u = ranges::unique(v);
    // v.erase(A(u));

    struct Event{
        ll time,type;
    };
    auto cmp = [](Event a,Event b){
        if(a.time == b.time) return a.type==close;
        return a.time<b.time;
    };
    set<ll> del;
    vector<Event> sweep;
    for(ll x : v){
        sweep.push_back({x-R,open});
        sweep.push_back({x+R+1,close});
    } ranges::sort(sweep,cmp);

    while(not v.empty()){
        ll mx = 0;
        for(ll cur = 0; auto [time,type] : sweep){
            if(type==open and del.contains(time+R)) continue;
            if(type==close and del.contains(time-R-1)) continue;
            if(type==open) cur++;
            else cur--;
            mx = max(cur,mx);
        }

        ll bomb_spot = -(ll)1e9;
        for(ll cur = 0; auto [time,type] : sweep){
            if(type==open and del.contains(time+R)) continue;
            if(type==close and del.contains(time-R-1)) continue;
            if(type==open) cur++;
            else cur--;
            if(cur==mx){
                bomb_spot=time;break;
            }
        }
        
        assert(bomb_spot not_eq -(ll)1e9);
        assert(mx);

        ans.push_back(bomb_spot);

        auto good = [&](ll spot){
            return abs(spot-bomb_spot)>R;
        };

        ranges::sort(v,[&](ll spot1,ll spot2){
            return !good(spot1)<!good(spot2);
        });

        while(not v.empty() and !good(v.back())) 
            del.insert(v.back()),v.pop_back();
    }

    cout << len(ans) << '\n';
    ranges::copy(ans,oit<ll>()),cout << '\n';
}

int main()
{
    //KING OF THE WORLD...... U.W.T.B
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    run();
}