#include<bits/stdc++.h>

using namespace std;

using pii=pair<long long, int>;

#define rep(i, n) for (int i = 0; i < n; i++)
#define sz(x) (long long)(x).size()
int main(){
    long long n, d; cin >> n >> d;
    vector<int> points;
    rep(i, n) {
        int a; cin >> a;
        points.push_back(a);
    }
    sort(points.begin(), points.end());
    vector<pii> pts;
    int laste = points[0];
    int cnt = 1;
    rep(i, n-1) {
        if (points[i+1]==points[i]) cnt++;
        else {
            pts.push_back({laste, cnt});
            
            cnt = 1;
            laste = points[i+1];
        }
    }
    pts.push_back({laste, cnt});
    vector<bool> used (sz(pts), false);
    vector<long long> out;
    rep(iter, 40) {
        int mxPts = 0;
        
        long long mxidx = 1e9;
        
        rep(l, sz(pts)) {
            if (used[l]) continue;
            int c = 0;
            int r = l;
            int last = l;
            while (r < sz(pts) and pts[r].first - 2*d <= pts[l].first) {
                if (!used[r]) c+=pts[r].second, last = r;
                r++;
            }
            // cout << pts[l].first << ' ' << pts[last].first << endl;
            if (c>mxPts) {
                // cout << "YES" << endl;
                mxPts = c;
                mxidx = pts[last].first-2*d;
            }
            c-=pts[l].second;
        }
        if (mxidx==1e9) break;
        out.push_back(mxidx+d);
        rep(i, sz(pts)) {
            if (pts[i].first >= mxidx and pts[i].first <= mxidx+2*d) used[i] = true;
            // cout << used[i] << ' ';
        }
        // cout << endl;

    }
    cout << sz(out) << endl;
    rep(i, sz(out)) {
        cout << out[i] << ' ';
    }
    cout << endl;
    return 0;
}