program economii;
var v, rez : array[0..1001] of integer;
    uz : array[0..50001] of boolean;
    i, j, N, nr : integer;
    f, g : text;


procedure sort(p,q:integer);
var st, dr, m, aux:integer;
begin
        st := p;
        dr := q;
        m := v[(st + dr) div 2];
        while (st < dr) do
        begin
                while (v[st] < m) do inc(st);
                while (v[dr] > m) do dec(dr);
                if (st<=dr) then
                begin
                        aux := v[st];
                        v[st] := v[dr];
                        v[dr] := aux;
                        inc(st);
                        dec(dr);
                end;
        end;
        if (st < q) then sort(st,q);
        if (dr > p) then sort(p,dr);

end;

begin
        assign(f,'economie.in'); reset(f);
        readln(f,N);
        for i := 1 to N do readln(f,v[i]);
        sort(1,N);
        for i:=1 to N do
        begin
                if not(uz[v[i]]) then
                begin
                        inc(nr);
                        rez[nr] := v[i];
                        uz[v[i]] := true;
                        for j :=1 to (v[N] - v[i]) do
                        if (uz[j]) then
                                uz[j+v[i]] := true;
                end;


        end;
        close(f);
        assign(g,'economie.out'); rewrite(g);
        writeln(g,nr);
        for i:=1 to nr do
                writeln(g,rez[i]);
        close(g);

end.