// #define NDEBUG
#include<bits/stdc++.h>
#define For(i,j,k) for(int i=(j);i<=(k);i++)
#define ForD(i,j,k) for(int i=(j);i>=(k);i--)
#define int long long
#define endl '\n'
using namespace std;
bool Mbe;
const int N=15;
int m,n;
int a[N];
#define pb push_back
#define pii pair<int,int>
vector<int> ans;
// first : the seg length ; second : the tot length should < ...
map<vector<pii>,bool> mp[N];
void dfs(int pos,vector<pii> &V){
    if((int)V.size()>pos+1) return;
    int sum=0;
    for(auto [x,y]:V) sum+=x;
    if(sum>m) return;
    sort(V.begin(),V.end());
    if(pos==0){
        if(V[0].second>m) ans.pb(V[0].first);
        return;
    }
    if(mp[pos].count(V)) return;
    mp[pos][V]=1;
    vector<pii> tmp;
    bool flg=1;
    for(auto [x,y]:V){
        if(x>=a[pos]){flg=0; break;}
        tmp.pb({x,min(a[pos],y)});
    }
    if(flg) dfs(pos-1,tmp);
    For(i,0,(int)V.size()-1) For(j,i+1,(int)V.size()-1){
        tmp.clear();
        For(k,0,(int)V.size()-1) if(i!=k&&j!=k) tmp.pb(V[k]);
        tmp.pb({V[i].first+V[j].first+a[pos],V[i].second+V[j].second+a[pos]});
        dfs(pos-1,tmp);
    }
}
void solve(){
    cin>>m>>n;
    For(i,1,n) cin>>a[i];
    vector<pii> V;
    For(i,1,n+1){
        V.pb({0,m+1});
        dfs(n,V);
    }
    sort(ans.begin(),ans.end());
    ans.erase(unique(ans.begin(),ans.end()),ans.end());
    cout<<(int)ans.size()<<endl;
    for(int x:ans) cout<<x<<' ';
    cout<<endl;
}
bool Med;
signed main(){
    fprintf(stderr,"%.3lf MB\n",(&Mbe-&Med)/1048576.0);
    // freopen("2.in","r",stdin), freopen("2.out","w",stdout);
    ios::sync_with_stdio(false); cin.tie(0),cout.tie(0);
    int _=1;
    // cin>>_;
    while(_--) solve();
    cerr<<1e3*clock()/CLOCKS_PER_SEC<<" ms\n";
    return 0;
}