#include<stdio.h>
#define nmax 50005
int t, n, poz, i, niv;
bool ok;
int v[nmax];

void parcurgere()
{
    niv++;
    if (niv>v[poz])
      ok=0;
    if (niv==v[poz])
      poz++;
    else
      if ((niv<v[poz])&&(ok))
        {
          parcurgere();
          parcurgere();
        }
    niv--;
}

int main()
{
  freopen("nivele.in","r",stdin);
  freopen("nivele.out","w",stdout);
  scanf("%ld",&t);
  while (t)
  {
    scanf("%ld",&n);
    for (i=1;i<=n;i++)
      scanf("%ld",&v[i]);
    poz=1;  ok=1; niv=0;
    parcurgere();
    if (ok)
      printf("DA\n");
    else
      printf("NU\n");
    t--;
  }
  return 0;
}