# Summary Power | Codechef solution

You work as an engineer. You were given an empty board with $�$ consecutive cells; at any moment, each cell can display one character.

You want the board to display a string $�$ with length $�>�$. Since the board isn't large enough, you want to display the string in $�-�+1$ steps. In the $�$-th step ($1\le �\le �-�+1$), you'll make the board display the characters ${�}_{�},{�}_{�+1},\dots ,{�}_{�+�-1}$.

The power required to switch the board from step $�$ to step $�+1$ (for $1\le �\le �-�$) is equal to the number of characters displayed on the board that have to change between these steps. You should find the total power required for the whole process of displaying a string, i.e. the sum of powers required for switching between all consecutive pairs of steps.

### Input

• The first line of the input contains a single integer $�$ denoting the number of test cases. The description of $�$ test cases follows.
• The first line of each test case contains two space-separated integers $�$ and $�$.
• The second line contains a single string $�$ with length $�$.

### Output

For each test case, print a single line containing one integer — the total power required for text switching.

### Constraints

• $1\le �\le 1,000$
• $2\le �\le 1{0}^{5}$
• $1\le �<�$
• each character of $�$ is a lowercase English letter
• the sum of $�$ for all test cases does not exceed $1{0}^{6}$

• $1\le �\le 100$
• $2\le �\le 50$

Subtask #2 (80 points): original constraints

### Sample 1:

Input
Output
3
6 3
aabbcc
5 2
abccc
4 3
aabb
4
3
1

### Explanation:

Example case 1:

• In step $1$, the board is displaying "aab".
• In step $2$, the board is displaying "abb".
• In step $3$, the board is displaying "bbc".
• In step $4$, the board is displaying "bcc".

The power required for switching from the $1$-st to the $2$-nd step is $1$, because cell $1$ changes from 'a' to 'a' (requiring power $0$), cell $2$ changes from 'a' to 'b' (requiring power $1$) and cell $3$ changes from 'b' to 'b' (requiring power $0$); $0+1+0=1$.

The power required for switching between the $2$-nd and $3$-rd step is $2$ and the power required for switching between the $3$-rd and $4$-th step is $1$.

Therefore, the answer is $1+2+1=4$.

Code(C++):-

Code(JAVA):-

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