#include<iostream>
#include<bitset>
using namespace std;
int n,tot;
int a[505];
bitset<500005> pref[505];
bitset<500005> suff[505];
int variante[250005],cntv;
int newv[250005],cntnew;
int sump[505];
signed main()
{
ios_base::sync_with_stdio(0);cin.tie(0);
cin>>n;
for(int i=1;i<=n;i++)
{
cin>>a[i];
tot+=a[i];
sump[i]=sump[i-1]+a[i];
}
pref[0][250000]=1;
for(int i=1;i<=n;i++)
pref[i] = ((pref[i-1]<<a[i]) | (pref[i-1]>>a[i]));
suff[n+1][250000]=1;
for(int i=n;i>0;i--)
suff[i] = ((suff[i+1]<<a[i]) | (suff[i+1]>>a[i]));
if(pref[n][250000]==0)
{
cout<<0;
return 0;
}
for(int i=1;i<=tot;i++)
variante[++cntv]=i;
for(int i=1;i<=n;i++)
{
cntnew=0;
for(int j=1;j<=cntv;j++)
{
int x = variante[j];
for(int difs=-sump[i-1];difs<=sump[i-1];difs++)
{
///difs + difd + x = 0 => difd = -difs - x
///difs + difd - x = 0 => difd = -difs + x
if((-tot<=-difs-x && -difs-x<=tot && pref[i-1][difs+250000] && suff[i+1][-difs-x+250000]) || (-tot<=-difs+x && -difs+x<=tot && pref[i-1][difs+250000] && suff[i+1][-difs+x+250000]))
{
newv[++cntnew] = variante[j];
break;
}
}
}
cntv = cntnew;
for(int j=1;j<=cntnew;j++)
variante[j] = newv[j];
}
cout<<cntv<<"\n";
for(int i=1;i<=cntv;i++)
cout<<variante[i]<<" ";
return 0;
}
/**
difs + difd +- x = 0 => x = abs(difs + difd)
x = difs + difd
sau
x = -difs - difd
4
1 3 1 5
6
3 5 7 11 9 13
*/
