#include<stdio.h>
FILE *f,*g;
long i,j,n,vmax,nrv;
long a[1001],sol[1001];
int v[5001];
long poz(long li,long ls)
{
long t=0,i,j,aux;
i=li;
j=ls;
while(i<j)
{
if(a[i]>a[j])
{
aux=a[i];
a[i]=a[j];
a[j]=aux;
t=1-t;
}
if(t)
j--;
else
i++;
}
return i;
}
void quick(long li,long ls)
	{
	long k;
	if(li<ls)
	{
		k=poz(li,ls);
		quick(li,k-1);
		quick(k+1,ls);
	}
	}
int main(void)
{
f=fopen("economie.in","r");
g=fopen("economie.out","w");
fscanf(f,"%ld",&n);
for(i=1;i<=n;i++)
{
fscanf(f,"%ld",&a[i]);
if(a[i]>vmax);
vmax=a[i];
}
quick(1,n);
nrv=0;
v[0]=1;
for(i=1;i<=n;i++)
{
if(!v[a[i]])
{
for(j=0;j<=vmax;j++)
if(v[j]==1&&v[j+a[i]]!=1)
v[j+a[i]]=1;
nrv++;
sol[nrv]=a[i];
}
}
fprintf(g,"%ld\n",nrv);
for(i=1;i<=nrv;i++)
fprintf(g,"%ld\n",sol[i]);
fclose(f);
fclose(g);
return 0;
}