program ultimaCifra;

var
  pc:integer;
  uc:integer;
  rez:integer;
  f,g:text;
  i,t:integer;

function fx(n:integer):integer;
begin
  case n of
   0: fx:=0;
   1: fx:=1;
   2: fx:=5 + (((pc mod 2) * 2) mod 2) * 2;
   3: fx:=2;
   4: fx:=8;
   5: fx:=3;
   6: fx:=9;
   7: fx:=2;
   8: fx:=0;
   9: fx:=9;
  end;
end;

begin
  assign(f,'cifra.in');
  reset(f);
  assign(g,'cifra.out');
  rewrite(g);

  {uc := 0;
  read(f,t);

  for i:=1 to t do begin}
     {readln(f);}
     pc:=0;
     {read(f,uc);}
    {while not(eoln(f)) do begin
       pc := uc;
       read(f,uc);
     end;
     rez:=(3 * pc + (pc mod 2) * 2 + fx(uc)) mod 10;
     writeln(g, rez);
  end;    }
  close(g);
  close(f);
end.