codeforces#P1433F. Zero Remainder Sum
Zero Remainder Sum
Description
You are given a matrix $a$ of size $n \times m$ consisting of integers.
You can choose no more than $\left\lfloor\frac{m}{2}\right\rfloor$ elements in each row. Your task is to choose these elements in such a way that their sum is divisible by $k$ and this sum is the maximum.
In other words, you can choose no more than a half (rounded down) of elements in each row, you have to find the maximum sum of these elements divisible by $k$.
Note that you can choose zero elements (and the sum of such set is $0$).
The first line of the input contains three integers $n$, $m$ and $k$ ($1 \le n, m, k \le 70$) — the number of rows in the matrix, the number of columns in the matrix and the value of $k$. The next $n$ lines contain $m$ elements each, where the $j$-th element of the $i$-th row is $a_{i, j}$ ($1 \le a_{i, j} \le 70$).
Print one integer — the maximum sum divisible by $k$ you can obtain.
Input
The first line of the input contains three integers $n$, $m$ and $k$ ($1 \le n, m, k \le 70$) — the number of rows in the matrix, the number of columns in the matrix and the value of $k$. The next $n$ lines contain $m$ elements each, where the $j$-th element of the $i$-th row is $a_{i, j}$ ($1 \le a_{i, j} \le 70$).
Output
Print one integer — the maximum sum divisible by $k$ you can obtain.
Samples
3 4 3
1 2 3 4
5 2 2 2
7 1 1 4
24
5 5 4
1 2 4 2 1
3 5 1 2 4
1 5 7 1 2
3 8 7 1 2
8 4 7 1 6
56
Note
In the first example, the optimal answer is $2$ and $4$ in the first row, $5$ and $2$ in the second row and $7$ and $4$ in the third row. The total sum is $2 + 4 + 5 + 2 + 7 + 4 = 24$.