Program dudy;
   var t,j,p,i,s,x,z,q:integer;
       g,f:text;
   begin
   assign (g,'cifre.in');
   assign (f,'cifre.out');
   reset (g);
   rewrite (f);

  read (g,t);

  for i:=1 to t do
  begin
   read (g,q);
   s:=0;
   for j:=1 to q do
    begin
      x:=1;
      For p:=1 to j do
       begin
        x:=x*j;
       end;
    s:=s+x;
    end;


      z:=s mod 10;
      writeln(f,z);
 end;
 close(f);
 close(g);
 end.