#include<stdio.h>
#include<string.h>
#include<math.h>
int num[10005];
int ans[10005];
int c[10005],temp[10005];
int main(){
   int n;
   while(scanf("%d",&n)!=EOF){
      memset(num,0,sizeof(num));
      memset(c,0,sizeof(c));
      memset(ans,0,sizeof(ans));
      memset(temp,0,sizeof(temp));
      int total=0;
      for(int i=0;i<n;i++){
        scanf("%d",&num[i]);
          total+=num[i];
        }
      for(int i=0;i<=num[0];i+=num[0])
        c[i]=1;
      for(int i=1;i<n;i++){
        for(int j=0;j<=total;j++){
            for(int k=0;k+j<=total&&k/num[i]<=1;k+=num[i]){///注意《=1
                temp[j+k]+=c[j];
                temp[(int)fabs(j-k)]+=c[j];//注意此刻应当考虑负值的情况
            }

        }
        for(int ii=0;ii<=total;ii++)
            c[ii]=temp[ii];

      }

    int cnt=0;
    for(int i=1;i<=total;i++){
        if(!c[i]){
            cnt++;
            ans[cnt]=i;
        }
    }
    printf("%d\n",cnt);
    for(int i=1;i<=cnt;i++){
        printf("%d%c",ans[i],i==cnt?‘\n‘:‘ ‘);
    }
   }
   return 0;
}