#include<stdio.h>
int v[ 50010 ],i,j,k,l,m,n,t,lvl;
bool ok;

bool test(){
if(lvl == v[k]){k++;return true;}
if(lvl > v[k])return false;
lvl++;
bool ok = test() && test();
lvl--;
}

int main(){
freopen("nivele.in","r",stdin);
freopen("nivele.out","w",stdout);

scanf("%d",&t);

for(;t;--t)
	{scanf("%d",&n);
	for(i = 1 ; i <= n ; i++)
		scanf("%d",&v[i]);
	v[n+1] = 0;
	k = 1;
	lvl = 1;
	ok = test();
	if(ok)
		printf("DA\n");
	else
		printf("NU\n");
	
	}

return 0;}