var x,y:char;
    t,n,i,r:integer;
    f,g:text;

begin
assign(f,'cifra.in');
reset(f);
readln(f,t);
y:='0';
assign(g,'cifra.out');
rewrite(g);
for i:=1 to t do begin
   y:='0';
   while not eoln(f) do begin
      x:=y;
      read(f,y);
   end;
   readln(f);
   n:=ord(y)+10*ord(x)-11*ord('0');
   r:=(n div 20)*4;
   n:=n mod 20;
   case n of
      0:r:=r+0;
      1,17:r:=r+1;
      3,7:r:=r+2;
      5,14:r:=r+3;
      12,16,19:r:=r+4;
      2,18:r:=r+5;
      9,10,13:r:=r+7;
      4,8,11,15:r:=r+8;
      6:r:=r+9
   end;
   writeln(g,r mod 10);
end;
close(g);
end.