然后就动不了了。
var
a,b,i,t,total:integer;
function f(x:integer):integer;
var
j,s:integer;
begin
for j:=1 to a-1 do
begin
{\\\\\\\}while x mod j = 0 do begin s:=s+j; x:=x div j; end;
end;
f:=s;
end;
begin
readln(a,b);
for i:=a to b do
begin
t:=f(i);
if f(t)=i then inc(total);
end;
writeln(total div 2);
end.