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: Accepted)

$n, $m, $q = gets.chomp.split(" ").map(&:to_i)
$a = []
$b = []
$c = []
$d = []
$q.times do |i|
  $a[i], $b[i], $c[i], $d[i] = gets.chomp.split(" ").map(&:to_i)
end
$max = 0

def calc(arr)
  # p arr
  score = 0
  $q.times do |i|
    # p "#{$b[i]} #{$a[i]}"
    score += $d[i] if arr[$b[i]] - arr[$a[i]] == $c[i]
    # p score
  end
  $max = $max >= score ? $max : score
end

def dfs(arr)
  if arr.length == $n+1
    return calc(arr)
  end
  arr.last.upto($m) do |v|
    # p arr
    dfs(arr + [v])
  end
end

def main()
  dfs([1])
  puts $max
end

main()