codeforces 1283D（BFS）

#include<bits/stdc++.h>
#define x first
#define y second
#define PB push_back
#define mst(x,a) memset(x,a,sizeof(x))
#define all(a) begin(a),end(a)
#define rep(x,l,u) for(ll x=l;x<u;x++)
#define rrep(x,l,u) for(ll x=l;x>=u;x--)
#define sz(x) x.size()
#define ins(x) inserter(x,x.begin())
#define IOS ios::sync_with_stdio(false);cin.tie(0);
using namespace std;
typedef unsigned long long ull;
typedef pair<int,int> PII;
typedef pair<long,long> PLL;
typedef pair<char,char> PCC;
typedef long long ll;
const int N=4*1e5+10;
const int M=1e6+10;
const int INF=0x3f3f3f3f;
const int MOD=1e9+7;
void solve(){
    queue<PII> q;
    vector<int> v;
    ll ans=0;
    map<int,int> used;
    int n,m;cin>>n>>m;
    rep(i,0,n){
        int x;cin>>x;
        used[x]=1;
        q.push({x+1,1});
        q.push({x-1,1});
    }
    while(m>0 && q.size()){
        PII cur=q.front();q.pop();
        if(!used[cur.x]){
            ans+=cur.y;
            used[cur.x]=1;
            m--;
            v.PB(cur.x);
        }
        if(!used[cur.x+1]) q.push({cur.x+1,cur.y+1});
        if(!used[cur.x-1]) q.push({cur.x-1,cur.y+1});
    }
    cout<<ans<<endl;
    rep(i,0,v.size()) cout<<v[i]<<' ';
    cout<<endl;
}
int main(){
    IOS;
    //int t;cin>>t;
    //while(t--){
        solve();
    //}
    return 0;
}