// Arhiva de probleme - Nivele


var
    t, n, i, j, ok, x, nst  : longint;
    f, g : text;
    st : array [1..50010] of longint;

begin
assign  (f, 'nivele.in');
assign  (g, 'nivele.out');
reset   (f);
rewrite (g);

readln  (f, t);
repeat
    read    (f, n);
    read    (f, st[1]);
    nst := 1;
    for i := 2 to n do
        begin
        read (f,x);
        inc (nst);
        st [nst] := x;
        while (nst > 1) and (st[nst] = st[nst-1]) do
               begin
               dec(nst);
               dec(st[nst]);
               end;

        end;
    readln  (f);
    if (nst = 1) and (st[1] = 1) then
        writeln  (g, 'DA')
    else
        writeln  (g, 'NU');

    dec     (t);
until t = 0;

close   (f);
close   (g);
end.