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 Rust (1.42.0) (judge verdict: Accepted)

// -*- coding:utf-8-unix -*-


use proconio::input;

// ABC086C - Traveling
// https://atcoder.jp/contests/abs/fasks/arc089_a

fn dfs(sta:usize,n:usize,m:usize,retu:&mut Vec<i32>,abcd:&Vec<(i32,i32,i32,i64)>) -> i64 {
    let mut res = 0i64;
    if n  == retu.len() {
        for &(a,b,c,d) in abcd.iter(){
            if retu[(b - 1) as usize] - retu[(a - 1) as usize] == c {
                res += d;
            }
        }
        return res;
    }
    for i in sta..=m{
        retu[n] = i as i32;
        let curres = dfs(i,n + 1,m,retu,abcd);
        if res < curres {
            res = curres;
        }
    }
    res
}
fn main() {
/*     input! {
        n: usize,
        mut plan: [(i32, i32, i32); n],  // Vec<(i32, i32, i32)>
    }
 */
    input! {
        n: usize,
        m: usize,
        q: usize,
        mut abcd: [(i32,i32,i32,i64); q],
    }

    let result = dfs(1,0,m,&mut vec![0;n],&abcd);
    println!("{}",result);
}