var n,i,j,s,r:integer;
    c:char;
    f,g:text;

function pu(x:integer):integer;
var i,k:integer;
begin
k:=1;
for i:=1 to x do
  begin
    k:=k*x;
    k:=k mod 10;
  end;
end;

begin
  assign(f,'cifra.in');
  assign(g,'cifra.out');
  reset(f);
  rewrite(g);
  readln(f,n);
  for i:=1 to n do
    begin
      s:=0;
      repeat
        read(f,c);
        r:=ord(c)-48;
        for j:=1 to r do
          s:=(s mod 10)+pu(j);
      until(eoln(f));
      readln(f);
      writeln(g,s mod 10);
    end;
  close(g);
end.