#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
const ll N=15,M=(1<<14)+3,INF=1e18;
ll n,m,a[N],sum[M];
unordered_map<ll,ll>F[N][M];
ll Dfs(ll x,ll S,ll T)
{
	if(x==n)return INF;
	if(F[x][S].count(T))return F[x][S][T];
	ll &s=F[x][S][T];s=-INF;
	if(!(S>>x&1))return s=min(a[x],Dfs(x+1,S,T));
	if(!(T>>x&1))return s=Dfs(x+1,S^(1<<x),T);
	int now=T^(1<<x);S^=1<<x;
	for(int v=now;;v=(v-1)&now)
	{
		s=max(s,Dfs(x+1,S,v)+Dfs(x+1,S,now^v));
		if(!v)break;
	}
	return s+=a[x];
}
int main()
{
	cin>>m>>n;set<ll>ans;
	for(int i=0;i<n;i++)cin>>a[i];
	for(int S=0;S<(1<<n);S++)sum[S]=sum[S^(S&-S)]+a[__builtin_ctz(S)];
	for(int S=0;S<(1<<n);S++)if(sum[S]<=m&&m<Dfs(0,S,S))ans.insert(sum[S]);
	cout<<ans.size()<<endl;
	for(auto it:ans)cout<<it<<" ";
}