**Problem**

Lisa just got a new math workbook. A workbook contains exercise problems, grouped into chapters.

- There are n chapters in Lisa’s workbook, numbered from 1 to n.
- The i-th chapter has ti problems, numbered from 1 to ti.
- Each page can hold
*up to*k problems. There are no empty pages or unnecessary spaces, so only the last page of a chapter 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.

Lisa believes a problem to be *special* if its index (within a chapter) is the same as the page number where it’s located. Given the details for Lisa’s workbook, can you count its number of *special* problems?

**Note:** See the diagram in the *Explanation* section for more details.

**Input Format**

The first line contains two integers n and k — the number of chapters and the maximum number of problems per page respectively.

The second line contains n integers t1,t2,…,tn where ti denotes the number of problems in the ii-th chapter.

**Constraints**

- 1≤n,k,ti≤100

**Output Format**

Print the number of *special* problems in Lisa’s workbook.

**Sample Input**

```
5 3
4 2 6 1 10
```

**Sample Output**

```
4
```

**Explanation**

The diagram below depicts Lisa’s workbook with n=5 chapters and a maximum of k=3 problems per page. Special problems are outlined in red, and page numbers are in yellow squares.

There are 4 special problems and thus we print the number 4 on a new line.