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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

	static Scanner scanner;

	//static List<Integer> E = new ArrayList<Integer>();
	static int N;
	static int M;
	static int Q;
	static int[] A;
	static int[] B;
	static int[] C;
	static int[] D;
	static int max=0;

	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

	    N=gi();
	    M=gi();
	    Q=gi();
	    A=new int[Q];
	    B=new int[Q];
	    C=new int[Q];
	    D=new int[Q];

	    for (int i=0; i<Q; i++) {
	    	A[i]=gi();
	    	B[i]=gi();
	    	C[i]=gi();
	    	D[i]=gi();

	    }

	    List<Integer> E=new ArrayList<Integer>();
	    f(E);
	    	System.out.print(max);

//        if (flg) {
//        	System.out.print("YES");
//        }else {
//        	System.out.print("NO");
//        }


	}

	public static void f(List<Integer> E) {
		if (E.size()==N) {
			int num=0;
			for (int i=0; i<Q; i++) {
				if(E.get(B[i]-1) - E.get(A[i]-1) == C[i]) {
					num+=D[i];
				}
			}
			if (max<num) {
				max=num;
			}
          return;
		}
		int start=1;
		if(E.size() !=0) {
			start=E.get(E.size() - 1);
		}
		for (int i=start; i<=M; i++) {
			List<Integer> nE=new ArrayList<Integer>();
			nE.addAll(E);
			nE.add(i);
			f(nE);
		}
	}
	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
}