#include<cstdio>
#include<algorithm>

#define NMAX 50007

using namespace std;

bool v[NMAX];
int n, nr, c[NMAX], a[1007];

void ciurdif(){
    c[1] = a[1];
    nr = 1;
    for(int i = 0; i <= 50000; i += a[1])
        v[i] = 1;
    for(int i = 2; i <= n; ++i)
        if(v[a[i]] == 0){
            c[++nr] = a[i];
            v[a[i]] = 1;
            for(int j = 1; j <= 50000; ++j)
                if(v[j] == 1 && j + a[i] <= 50000)
                    v[j + a[i]] = 1;
        }
}
int main(){
    freopen("economie.in", "r", stdin);
    freopen("economie.out", "w", stdout);
    scanf("%d", &n);
    for(int i = 1; i <= n; ++i)
        scanf("%d", &a[i]);
    sort(a + 1, a + n + 1);
    ciurdif();
    printf("%d\n", nr);
    for(int i = 1; i <= nr; ++i)
        printf("%d\n", c[i]);
    return 0;
}