var t,n,i,a:longint;
    f,g:text;
    x,y:char;

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(x)-ord('0'))*10+ord(y)-ord('0');
   a:=n div 20;
   n:=n mod 20;
   a:=(a*4) mod 10;
   case n of
      1,17:a:=a+1;
      3,7:a:=a+2;
      5,13:a:=a+3;
      12,16:a:=a+4;
      2,18:a:=a+5;
      9,10,13:a:=a+7;
      4,8,15:a:=a+8;
      6:a:=a+9;
   end;
   writeln(g,a mod 10);
end;
close(g);
end.