program qinheshu;
var
  jilu1,jilu2,t,n,m,q,j:longint;
  biaozhi:array [1..100000000] of 0..1;
procedure yinzihe(x:longint);
var
  i:integer;
begin
  t:=0;
  for i:=1 to trunc(sqrt(x)) do
    if x mod  i=0 then
    t:=t+i+(x div i);
  t:=t-x
end;
begin
  assign (input,'amicable.in');
  reset (input);
  assign (output,'amicable.out');
  rewrite (output);
  read (n,m);
  for j:=n to m do
  begin
    if biaozhi[j]=0 then
    begin
      yinzihe(j);
      jilu1:=j;
      jilu2:=t;
      if t<=m then
      begin
        yinzihe(t);
        if t=jilu1 then
        begin
          q:=q+1;
          biaozhi[jilu2]:=1
        end
      end
    end
  end;
  write (q);
  close (input);
  close (output)
end.