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 Python (3.8.2) (judge verdict: Accepted)

# 入力
N, M, Q = map(int, input().split())
a = [0] * Q
b = [0] * Q
c = [0] * Q
d = [0] * Q
for i in range(Q):
    a[i], b[i], c[i], d[i] = map(int, input().split())
    a[i] -= 1
    b[i] -= 1

# スコア計算
def score(A):
    tmp = 0
    for ai, bi, ci, di in zip(a, b, c, d):
        if A[bi] - A[ai] == ci:
            tmp += di
    return tmp

# DFS
def dfs(A):
    if len(A) == N:
        return score(A) # 数列 A のスコアを返す
    res = 0
    prev_last = A[-1] if len(A) > 0 else 0
    for v in range(prev_last, M):
        A.append(v)
        res = max(res, dfs(A)) # 再帰呼出しながら、スコア最大値も更新
        A.pop()
    return res

# 求める
print(dfs([]))