#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 14;
ll m;
int n,lim;
ll a[N];
int k;
int f[1<<N],g[1<<N];
ll sum[1<<N],cs[1<<N];
map<ll,int>mp;
vector<ll>vec;
void fmt(int A[])
{
    for(int i = 1;i < (1<<k);i<<=1)
        for(int j = 0;j < (1<<k);j+=i<<1)
            for(int l = 0;l < i;l++)
                A[i+j+l] += A[j+l];
    for(int i = 0;i < (1<<k);i++) A[i] *= A[i];
    for(int i = 1;i < (1<<k);i<<=1)
        for(int j = 0;j < (1<<k);j+=i<<1)
            for(int l = 0;l < i;l++)
                A[i+j+l] -= A[j+l];
    for(int i = 0;i < (1<<k);i++) if(A[i] > 0) A[i] = 1;
}
void work(int S)
{
    if(mp[sum[S]]) return ;
    if(sum[S] > m) return ;
    //cout<<S<<"\n";
    int cnt = 0;
    ll cur = 0;
    for(int i = 0;i < n;i++)
    {
        if(S & (1<<i))
        {
            cur += a[i];
            cnt++;
        }
        else if(cur + 1ll*a[i]*(cnt+1) <= m) return ;
    }
    k = 0;
    f[0] = 1;
    //cout<<S<<"\n";
    for(int i = n-1;i >= 0;i--)
    {
        //cout<<i<<"\n";
        if(S & (1<<i))
        {
            for(int j = 0;j < (1<<k);j++) g[j] = f[j];
            fmt(g);
            for(int j = (1<<k);j < (1<<k+1);j++) cs[j] = cs[j^(1<<k)] + a[i],f[j] = g[j^(1<<k)];
            ++k;
        }
        else
        {
            for(int j = 0;j < (1<<k);j++) if(cs[j] > a[i]) f[j] = 0;
        }
    }
    //cout<<S<<"\n";
    //cout<<S<<" "<<f[(1<<k)-1]<<"\n";
    if(f[(1<<k)-1]) mp[sum[S]] = 1,vec.push_back(sum[S]);
}
int main()
{
    ios::sync_with_stdio(false);cin.tie(0);
    cin>>m>>n;lim = (1<<n);
    for(int i = 0;i < n;i++) cin>>a[i];
    for(int i = 1;i < lim;i++)
    {
        int lb = __builtin_ctz(i);
        sum[i] = sum[i^(1<<lb)] + a[lb];
    }
    for(int S = 0;S < lim;S++) work(S);
    cout<<vec.size()<<"\n";
    sort(vec.begin(),vec.end());
    for(auto x:vec) cout<<x<<" ";
    cout<<"\n";
    return 0;
}