> #include<iostream>
> #include<vector>
> #include<fstream>
> #include<algorithm>
> 
> using namespace std;
> 
> vector<int> vec;
> bool record[1000];
> bool tmp[1000];
> int max_;
> bool signal;
> int limit;
> 
> void search(int i,int total,int m){
>     if(i==vec.size()){
>         if(total!=0)return;
>         if(m<max_){
>             signal=1;
>             max_=m;
>             /* cout<<max_<<endl; */
>             copy(tmp,tmp+vec.size(),record);
>            /*  for(int j=0;j<vec.size();j++){
>                 cout<<record[j];
>             }
>             cout<<endl;  */   
>         }    
>             
>         return ;
>     }
>     tmp[i]=1;
>     if(total>limit)return ;
>     search(i+1,total+vec[i],total+vec[i]>m?(total+vec[i]):m);
>     tmp[i]=0;
>     if(total-vec[i]<0)return ;
>     search(i+1,total-vec[i],m);
> }
> 
> int main(){
>     //ifstream cin("tmp.txt");
>     int count;
>     //cin>>count;
>     scanf("%d",&count);
>     int i,j;
>     while(count--){
>         int M;
>         //cin>>M;
>         scanf("%d",&M);
>         limit=0;
>         for(i=0;i<M;i++){
>             int in;
>             /* cin>>in; */
>             scanf("%d",&in);
>             vec.push_back(in);
>             limit+=in;
>         }
>         if(limit%2!=0){
>             cout<<"IMPOSSIBLE"<<endl;
>             vec.clear();
>             continue;
>         }
>         signal=0;
>         limit/=2;    
>         max_=1000000;
>         search(0,0,0);
>         if(signal){
>             for(i=0;i<vec.size();i++){
>                 if(record[i])cout<<"U";
>                 else cout<<"D";
>             }
>             cout<<endl;
>         }
>         else cout<<"IMPOSSIBLE"<<endl; 
>         vec.clear(); 
>     }
>     system("pause");
>     return 0;
> }              
>               
>     
>         
>