#include <stdio.h>
#define MAXN 1000
#define MAXV 50000
int v[MAXN], sol[MAXN], pot[MAXV+1];
int main(){
    int n, max, i, x, k, j, aux, pmin;
    FILE *fin, *fout;
    fin=fopen("economie.in", "r");
    fout=fopen("economie.out", "w");
    fscanf(fin, "%d", &n);
    max=0;
    for(i=0; i<n; i++){
        fscanf(fin, "%d", &v[i]);
        if(max<v[i]){
            max=v[i];
        }
    }
    for(i=0; i<n; i++){
        pmin=i;
        for(j=i+1; j<n; j++){
            if(v[pmin]>v[j]){
                pmin=j;
            }
        }
        if(pmin!=i){
            aux=v[pmin];
            v[pmin]=v[i];
            v[i]=aux;
        }
    }
    k=0;
    for(i=0; i<n; i++){
        if(pot[v[i]]==0){
            sol[k++]=v[i];
            pot[v[i]]=1;
            for(j=v[i]+1; j<=max; j++){
                if(pot[j-v[i]]==1){
                    pot[j]=1;
                }
            }
        }
    }
    fprintf(fout, "%d\n", k);
    for(i=0; i<k; i++){
        fprintf(fout, "%d\n", sol[i]);
    }
    fclose(fin);
    fclose(fout);
    return 0;
}