Problem:
Score : 400 points

Problem Statement

Takahashi had a pair of two positive integers not exceeding N, (a,b), which he has forgotten.
He remembers that the remainder of a divided by b was greater than or equal to K.
Find the number of possible pairs that he may have had.

Constraints

1 \leq N \leq 10^5

0 \leq K \leq N-1

All input values are integers.

Input

Input is given from Standard Input in the following format:

N K

Output

Print the number of possible pairs that he may have had.

Sample Input 1

5 2

Sample Output 1

7

There are seven possible pairs: (2,3),(5,3),(2,4),(3,4),(2,5),(3,5) and (4,5).

Sample Input 2

10 0

Sample Output 2

100

Sample Input 3

31415 9265

Sample Output 3

287927211

Solution in Pascal (FPC 2.6.2) (judge verdict: Accepted)

var
	n,k,ans:int64;
	b:Longint;
begin
	read(n,k);
	for b:=k+1 to n do begin
		inc(ans,n div b*(b-k));
		if n mod b>=k then inc(ans,n mod b-k+1);
	end;
	if k=0 then dec(ans,n);
	writeln(ans);
end.