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 Ruby (2.7.1) (judge verdict: Wrong Answer)

N,M,Q = gets.split.map(&:to_i)
a = []
b = []
c = []
d = []
Q.times do |i|
  a[i], b[i], c[i], d[i] = gets.split.map(&:to_i)
  a[i] -= 1
  b[i] -= 1
end

def score(array,a,b,c,d)
  tmp = 0
  for ai,bi,ci,di in a.zip(b,c,d)
    tmp += di if array[bi] - array[ai] == ci
  end
  tmp
end

def dfs(array,a,b,c,d)
  if array.length == N
    return score(array,a,b,c,d)
  end
  result = 0
  array.length > 0 ? (prev_last = array[-1]) : (prev_last = 0)
  for v in prev_last..M
    array.push(v)
    result = [result, dfs(array,a,b,c,d)].max
    array.pop
  end
  result
end

puts dfs(Array.new,a,b,c,d)