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)

/*
    Arnab Chanda 
*/

// All imports here

import java.io.InputStreamReader;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.InputStream;
import java.util.*;
import java.util.stream.Collectors;

// Template code starts here //

//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Debugger debug = new Debugger(out);
        Objectify objectify = new Objectify(debug);
        Task solver = new Task();
        int test = 1;
        while(test-->0){
            solver.solve(1, in, out, debug, objectify);
        }
		out.close();
	}
}

class InputReader {
    public BufferedReader reader;
    public StringTokenizer tokenizer;
 
    public InputReader(InputStream stream) {
        reader = new BufferedReader(new InputStreamReader(stream));
        tokenizer = null;
    }
 
    public String next() {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken();
    }
 
    public int nextInt() {
        return Integer.parseInt(next());
    }

    public long nextLong() {
        return Long.parseLong(next());
    }

    public Double nextDouble() {
        return Double.parseDouble(next());
    }

    public float nextFloat() {
        return Float.parseFloat(next());
    }
 
}

class Debugger{
    PrintWriter out;

    Debugger(PrintWriter out){    
        this.out = out;
    }

    public <T> void printList(List<T> arrayList){
        for( Object ob: arrayList){
            out.print(ob+" ");
        }
        out.println();
    }

    public <T> void printSet(Set<T> set){
        for(Object ob: set){
            out.print(ob+" ");
        }
        out.println();
    }

    public <T> void printMap(Map<?,?> map){
        for(Object ob: map.keySet()){
            System.out.println(ob+" : "+map.get(ob));
        }
    }
}

class Objectify{
    
    Debugger debug;

    Objectify(Debugger ob){ debug = ob; }

    public void printArr(int[] arr){ debug.printList(Arrays.stream(arr).boxed().collect(Collectors.toList())); }
    public void printArr(double[] arr){ debug.printList(Arrays.stream(arr).boxed().collect(Collectors.toList())); }
    public void printArr(long[] arr){ debug.printList(Arrays.stream(arr).boxed().collect(Collectors.toList())); }
    public void printArr(char[] arr){ debug.printList( String.valueOf(arr).chars().mapToObj(c -> (char) c).collect(Collectors.toList())); }
    public void printArr(String[] arr){ debug.printList(Arrays.asList(arr)); }

    public void printMatrix(int[][] arr){ for(int a[]:arr) printArr(a); }
    public void printMatrix(double[][] arr){ for(double a[]:arr) printArr(a); }
    public void printMatrix(long[][] arr){ for(long a[]:arr) printArr(a); }
    public void printMatrix(char[][] arr){ for(char a[]:arr) printArr(a); }
    public void printMatrix(String[][] arr){ for(String a[]:arr) printArr(a); }

}

//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// Template code ends here


class Task {

    final long MOD = (int)Math.pow(10,9)+7;

    int[][] queries;

    int max = 0;

    public int findScore(int[] arr){
        int score = 0;
        for(int i = 0; i < queries.length; i++){
            if (arr[queries[i][1]-1] - arr[queries[i][0]-1] == queries[i][2]) score+=queries[i][3];
        }
        return score;
    }

    public void findArray(int[] arr, int i, int m){
        if (i == arr.length){
            // for(int u =0; u<arr.length; u++){
            //     System.out.print(arr[u]+" ");
            // }
            // System.out.println();
            max = Math.max(max, findScore(arr));
            return;
        }
        // int x = Math.min(i+1, )
        int x = 0;
        if (i == 0){
            x = 1;
        }else{
            x = arr[i-1];
        }
        for(; x<=m; x++){
            arr[i] = x;
            findArray(arr, i+1, m);
        }
    }

    public void solve(int testNumber, InputReader sc, PrintWriter out, Debugger debug, Objectify objectify) {
        
        // write your code here
        int n = sc.nextInt();
        int m = sc.nextInt();
        int q = sc.nextInt();

        queries = new int[q][4];

        for (int i = 0 ; i < q; i++){
            int a = sc.nextInt();
            int b = sc.nextInt();
            int c = sc.nextInt();
            int d = sc.nextInt();
            queries[i] = new int[]{a,b,c,d};
        }

        int [] A = new int[n];

        findArray(A, 0, m);

        out.println(max);

    }
}