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.*;
 import java.math.BigInteger;
public class Main
{
	public static  void main(String args[])
	{
		Scanner sc=new Scanner(System.in);
		// String h[]=sc.nextLine().split(" ");
		// long n=Long.parseLong(sc.nextLine());
		String s[]=sc.nextLine().split(" ");
		int n=Integer.parseInt(s[0]);
		int m=Integer.parseInt(s[1]);
		int q=Integer.parseInt(s[2]);
		ArrayList<Pair>ch=new ArrayList<>();
		for(int i=0;i<q;i++)
		{
			String h[]=sc.nextLine().split(" ");
			ch.add(new Pair(Integer.parseInt(h[0]),Integer.parseInt(h[1]),Integer.parseInt(h[2]),Integer.parseInt(h[3])));
		}
		System.out.println(get(new int[n],1,0,ch,m));
	}
	static int get(int [] arr, int k, int i, ArrayList<Pair>ch, int m)
	{
		if(i==arr.length)
		{
			int sum=0;
			for(int u=0;u<ch.size();u++)
			{
				if(arr[ch.get(u).b-1]-arr[ch.get(u).a-1]==ch.get(u).c){sum+=ch.get(u).d;}
			}
			return sum;
		}
		int max=0;
		for(int u=k;u<=m;u++)
		{
			arr[i]=u;
			max=Math.max(max,get(arr,u,i+1,ch,m));
			
		}
		return max;
	}

}
class Pair
{
	int a;
	int b;
	int c;
	int d;
	Pair(int e,int f, int g,int h){
		a=e;
		b=f;
		c=g;
		d=h;
	}
}