const b:array[0..9] of array[0..3] of longint=((0,0,0,0),
(1,1,1,1),(6,2,4,8),(1,3,9,7),(6,4,6,4),(5,5,5,5),(6,6,6,6),
(1,7,9,3),(6,8,4,2),(1,9,1,9));
var  f,g:text;
     t,i,nr,j,a:longint;
     c1,c2:char;
begin
 assign(f,'cifra.in'); reset(f);
 assign(g,'cifra.out'); rewrite(g);
 readln(f,t);
 for i:=1 to t do begin
  read(f,c1,c2);
  if c2<>chr(13) then
   a:=(ord(c1)-48)*10+ord(c2)-48
  else
   a:=(ord(c1)-48);
  while not(eoln(f)) do begin
   read(f,c1);
   if ord(c1)<>13 then
    a:=(a*10+ord(c1)-48) mod 100;
  end;
  nr:=0;
  for j:=1 to a do
   inc(nr,b[j mod 10,j mod 4]);
  writeln(g,nr mod 10);
  readln(f);
 end;
 close(f); close(g);
end.