var t,x,y,s,n,i,j:longint;
    a:array[0..9,1..4]of integer;
    f,g:text; ss:string;  c:integer;

begin
for i:=0 to 9 do
    begin
     a[i,1]:=i;
     for j:=2 to 4 do
       a[i,j]:=(a[i,j-1]*i) mod 10;
    end;
assign(f,'cifra.in');
reset(f);
assign(g,'cifra.out');
rewrite(g);
readln(f,t);
for j:=1 to t do
 begin
  readln(f,ss);
  val(ss,n,c);
  s:=0;
  for i:=1 to n do
    begin
       x:=i mod 10;
       y:=i mod 4;
       if y=0 then y:=4;
       s:=s+a[x,y];
       s:=s mod 10;
    end;
  writeln(g,s);
 end;
close(f);
close(g);
end.