#include <bits/stdc++.h>

using namespace std;
ifstream fin("economie.in");
ofstream fout("economie.out");
int a[1001],sol[1001],ap[50001];
bitset<50001>es;
int n,i,mx,fi,j;
int main()
{
    fin>>n;
    for(i=1;i<=n;i++)fin>>a[i],ap[a[i]]++,mx=max(mx,a[i]);
    for(n=0,i=1;i<=mx;i++)
        while(ap[i]--)a[++n]=i;
    memset(ap,0,sizeof(ap));
    es[0]=1;
    fi=0;
    for(i=1;i<=n;i++)
    {
        if(!es[a[i]])
        sol[++fi]=a[i];
        for(j=0;j+a[i]<=50000;j++)
            if(es[j])
            es[j+a[i]]=1;

    }
    fout<<fi<<"\n";
    for(i=1;i<=fi;i++)fout<<sol[i]<<"\n";
    return 0;
}