var
count,i:integer;
f:text;
s:string;
begin
assign(f,'kot.txt');
reset(f);
count:= 0;
readln(f,s);
for i:= 1 to length(s) do begin
if s[i] = '(' then
inc(count)
else if s[i] = ')' then begin
dec(Count);
if count < 0 then
break;
end;
end;
if count <> 0 then
writeln('net')
else writeln('da');
close(f);
end.