#include<iostream>
#include<algorithm>

using namespace std;

int  d[50];
int  minh[50][1010];
char move[50][1010];

/*
 * minh[i][h] = lowest max height above ground to be at height h
 *             after distances d[0]..d[i]
 * 
 * move[i][h] = move to make for distance d[i] to end up at h in
 *              while achieving minh[i][h]
 */


const int infty = 1000000000;
	     
void solve()
{
  int m;
  cin >> m;
  int tot = 0;
  
  for (int i = 0; i < m; ++i) {
    cin >> d[i];
    tot += d[i];
  }
  
  for (int i = 0; i < m; ++i)
    for (int j = 0; j <= tot; ++j)
      minh[i][j] = infty;
  
  minh[0][d[0]] = d[0];
  move[0][d[0]] = 'U';
  for (int i = 1; i < m; ++i)
    for (int h = 0; h <= tot; ++h) {
      if (minh[i-1][h] != infty) {
	if (h >= d[i]) { // try climbing down
	  if (minh[i][h-d[i]] > minh[i-1][h]) {
	    minh[i][h-d[i]] = minh[i-1][h];
	    move[i][h-d[i]] = 'D';
	  }
	}
	// try climbing up
	int newminh = max(minh[i-1][h], h+d[i]);
	if (minh[i][h+d[i]] > newminh) {
	  minh[i][h+d[i]] = newminh;
	  move[i][h+d[i]] = 'U';
	}
      }
      

    }
  
  if (minh[m-1][0] == infty) 
    cout << "IMPOSSIBLE" << endl;
  else {
    char s[100];
    s[m] = 0;
    int h = 0;
    for (int i = m-1; i >= 0; --i) {
      s[i] = move[i][h];
      if (s[i] == 'U') h -= d[i];
      else h += d[i];
    }
    cout << s << endl;
  }
}



int  main()
{
  int n;
  
  for (cin >> n; n > 0; --n)
    solve();
  
  return 0;
}