program cifra;
const a:array[1..9]of byte=((1),(5),(2),(8),(3),(9),(2),(8),(7));
      b:array[1..9]of byte=((7),(4),(1),(8),(5),(2),(9),(6),(3));
var n:array[1..101]of char;
    t,i,s,j:integer;
    f,h:text;
begin
assign(f,'cifra.in');
assign(h,'cifra.out');
reset(f);rewrite(h);
readln(f,t);
for i:=1 to t do
 begin
  j:=1;
  while not seekeoln(f)do
   begin
     read(f,n[j]);
       inc(j);
   end;
  case n[j-2] of
   '1':s:=b[1];
   '2':s:=b[2];
   '3':s:=b[3];
   '4':s:=b[4];
   '5':s:=b[5];
   '6':s:=b[6];
   '7':s:=b[7];
   '8':s:=b[8];
   '9':s:=b[9];
   else s:=0;
   end;
   case n[j-1] of
   '1':s:=(s+a[1])mod 10;
   '2':s:=(s+a[2])mod 10;
   '3':s:=(s+a[3])mod 10;
   '4':s:=(s+a[4])mod 10;
   '5':s:=(s+a[5])mod 10;
   '6':s:=(s+a[6])mod 10;
   '7':s:=(s+a[7])mod 10;
   '8':s:=(s+a[8])mod 10;
   '9':s:=(s+a[9])mod 10;
   end;
   read(f,n[1]);
 writeln(h,s);
 end;
close(f);close(h);
end.