Yet Another Contest 2 P4 - No More Arithmetic
View as PDFMike is tired of performing arithmetic with squares, so he has decided to break his square up into an array  with 
 integers. Furthermore, Mike wants to reduce the size of his array, so he will continue to perform the following process, in order, until he is unable to.
- Select two integers 
and
in the array such that
and
.
 - Select one of the four operations:
. Mike may only select this operation if the result is an integer.
 - Increase the total score by the number obtained from performing the selected operation taken modulo 
.
 - Remove either 
or
from the array.
 
Your job is to help Mike find the maximum possible total score that can be obtained.
Constraints
 is a prime number.
Subtask 1 [10%]
Subtask 2 [20%]
Note that the previous subtask must be passed for this subtask to be evaluated.
Subtask 3 [20%]
Every element of  can be expressed in the form 
, where 
 and 
 are non-negative integers.
Subtask 4 [Up to 50%]
No additional constraints.
In order to obtain all  of the points allocated to this subtask, your submission must adhere to the following memory limits:
- In Python, your program must not exceed 
MB of memory usage. Python users are recommended to use Python 2/3 over PyPy 2/3 when submitting.
 - In Java, your program must not exceed 
MB of memory usage.
 - In all other languages, your program must not exceed 
MB of memory usage.
 
If your program produces the correct output on all test cases but does not adhere to the memory limits listed above, then it will only receive  out of the 
 of points available for this subtask.
Note that the memory constraints listed above only apply to this subtask.
Note that all previous subtasks must be passed for this subtask to be evaluated.
Input Specification
The first line contains two integers  and 
.
The next line contains .
Output Specification
On a single line, print the maximum possible score.
Sample Input 1
3 5
8 4 5
Sample Output 1
8
Explanation for Sample Output 1
Mike can first select  and 
. Then, he will choose the 
 operation and add 
 to the total score. Then, he will remove 
 from the array, so the array becomes 
.
Next, Mike selects  and 
. Then, he will choose the 
 operation and add 
 to the total score. Then, he will remove 
 from the array, so the array becomes 
.
Now, the array only consists of one integer. Mike is unable to perform any more moves, and his final score is . It can be shown that this is the maximal score.
Sample Input 2
4 2
1 1 1 1
Sample Output 2
3
Explanation for Sample Output 2
Since all elements in the array are equal, the choice of integers which Mike selects and deletes does not matter. Each time, he will choose the  or 
 operation and add 
 to his total score, resulting in a final score of 
.
Sample Input 3
4 7
5 11 42 7
Sample Output 3
17
Sample Input 4
5 13
6 432 209 420 9
Sample Output 4
45
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