Lisa just got a new math workbook. A workbook contains exercise problems, grouped into chapters. Lisa believes a problem to be special if its index (within a chapter) is the same as the page number where it’s located. The format of Lisa’s book is as follows:
- There are n chapters in Lisa’s workbook, numbered from 1 to n.
- The chapter has arr[i] problems, numbered from 1 to arr[i].
- Each page can hold up to k problems. Only a chapter’s last page of exercises may contain fewer than k problems.
- Each new chapter starts on a new page, so a page will never contain problems from more than one chapter.
- The page number indexing starts at 1.