Problem:
Score : 300 points

Problem Statement

Given are positive integers N, M, Q, and Q quadruples of integers ( a_i , b_i , c_i , d_i ).

Consider a sequence A satisfying the following conditions:

A is a sequence of N positive integers.

1 \leq A_1 \leq A_2 \le \cdots \leq A_N \leq M.

Let us define a score of this sequence as follows:

The score is the sum of d_i over all indices i such that A_{b_i} - A_{a_i} = c_i. (If there is no such i, the score is 0.)

Find the maximum possible score of A.

Constraints

All values in input are integers.

2 ≤ N ≤ 10

1 \leq M \leq 10

1 \leq Q \leq 50

1 \leq a_i < b_i \leq N ( i = 1, 2, ..., Q )

0 \leq c_i \leq M - 1 ( i = 1, 2, ..., Q )

(a_i, b_i, c_i) \neq (a_j, b_j, c_j) (where i \neq j)

1 \leq d_i \leq 10^5 ( i = 1, 2, ..., Q )

Input

Input is given from Standard Input in the following format:

N M Q
a_1 b_1 c_1 d_1
:
a_Q b_Q c_Q d_Q

Output

Print the maximum possible score of A.

Sample Input 1

3 4 3
1 3 3 100
1 2 2 10
2 3 2 10

Sample Output 1

110

When A = \{1, 3, 4\}, its score is 110. Under these conditions, no sequence has a score greater than 110, so the answer is 110.

Sample Input 2

4 6 10
2 4 1 86568
1 4 0 90629
2 3 0 90310
3 4 1 29211
3 4 3 78537
3 4 2 8580
1 2 1 96263
1 4 2 2156
1 2 0 94325
1 4 3 94328

Sample Output 2

357500

Sample Input 3

10 10 1
1 10 9 1

Sample Output 3

1

Solution in OCaml (4.10.0) (judge verdict: Accepted)

let n, m, q = Scanf.scanf "%d %d %d\n" (fun n m q -> n, m, q)

let a = Array.make q 0
let b = Array.make q 0
let c = Array.make q 0
let d = Array.make q 0

let rec f i =
  if i < q then (
      Scanf.scanf "%d %d %d %d\n" (fun w x y z ->
      a.(i) <- w - 1;
      b.(i) <- x - 1;
      c.(i) <- y;
      d.(i) <- z
    );
    f (i + 1)
  )

let rec g i j e ans =
  if j = n then (
      let rec h i ans =
        if i = q then ans
        else h (i + 1) (ans + if e.(b.(i)) - e.(a.(i)) = c.(i) then d.(i) else 0)
      in h 0 0
  ) else (
      let rec h i ans =
        if i = m + 1 then ans
        else (
            e.(j) <- i;
            h (i + 1) (max ans (g i (j + 1) e ans))
        )
      in h i 0
  )

let () =
  f 0;
  let ans = g 1 0 (Array.make n 0) 0 in
  Printf.printf "%d\n" ans