#arc091b. [arc091_b]Remainder Reminder

[arc091_b]Remainder Reminder

请求出有序正整数对 (a,b)(a,b) 的个数。每个对需要满足 1a,bN1\le a,b\le N ,且 amodbKa\bmod b\ge K

限制:1N105,0K<N1\le N\le 10^5,0\le K<N