var
n,m,chet: longint;
k,l,i: longint;
begin
readln(n,m);
if (m=n) or (m=0) or (m>n) then writeln('0') else begin
if (n-m)<m then begin k:=m; m:=n-m; end else k:=n-m;
repeat
k:=k+1;
l:=k;
i:=1;
 repeat
 i:=i+1;
  repeat
  if (l mod i)=0 then begin l:=l div i; chet:=chet+1; end;
  until (l mod i)>0;
 until (i=k) or (l=1);
{writeln(k, chet);     }
until k=n;
k:=1;
repeat
k:=k+1;
if k<(m+1) then begin
l:=k;
i:=1;
 repeat
 i:=i+1;
  repeat
  if (l mod i)=0 then begin l:=l div i; chet:=chet-1; end;
  until (l mod i)>0;
 until (i=k) or (l=1);
{writeln(k,' ', chet);    }
end;
until k>=m;
writeln(chet);                       end;
end.