using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using static System.Console;
using static System.Math;

namespace Atcoder
{
    class Program
    {
        static StreamWriter sw = new StreamWriter(OpenStandardOutput()) { AutoFlush = false };
        static void Main(string[] args)
        {
            try
            {
                SetOut(sw);
                Solve.Answer();
                Out.Flush();
            }
            catch (Exception ex)
            {
                WriteLine(ex.ToString());
            }
        }
    }

    public class Solve
    {
        public static void dfs(List<int> A, int n, int m, int q)
        {

            if (A.Count == n + 1)
            {
                int now = 0;
                for (int i = 0; i < q; i++)
                {
                    if (A[b[i]] - A[a[i]] == c[i]) now += d[i];
                }
                ans = Max(ans, now);
                return;
            }

            A.Add(A[A.Count - 1]);
            while (A[A.Count - 1] <= m)
            {
                dfs(A, n, m, q);
                A[A.Count - 1]++;
            }
            A.RemoveAt(A.Count - 1);
        }

        static int ans = 0;
        static List<int> a = new List<int>();
        static List<int> b = new List<int>();
        static List<int> c = new List<int>();
        static List<int> d = new List<int>();
        public static void Answer()
        {
            var nmq = IO.RSInt;
            var n = nmq[0];
            var m = nmq[1];
            var q = nmq[2];
            for (int i = 0; i < q; i++)
            {
                var work = IO.RSInt;
                a.Add(work[0]);
                b.Add(work[1]);
                c.Add(work[2]);
                d.Add(work[3]);
            }
            var tmp = new List<int>();
            tmp.Add(1);
            dfs(tmp, n, m, q);
            WriteLine(ans);
        }
    }

    public class IO
    {
        #region Input
        public static int RInt => int.Parse(ReadLine());
        public static long RLong => long.Parse(ReadLine());
        public static double RDouble => double.Parse(ReadLine());

        public static string[] RSString => ReadLine().Split();
        public static int[] RSInt => ReadLine().Split().Select(s => int.Parse(s)).ToArray();
        public static long[] RSLong => ReadLine().Split().Select(s => long.Parse(s)).ToArray();
        public static double[] RSDouble => ReadLine().Split().Select(s => double.Parse(s)).ToArray();
        #endregion

        #region Output
        public static void OutJoinSpace<T>(IEnumerable<T> list) => WriteLine(string.Join(" ", list));
        public static void WriteLineYes_or_No(bool flag) => WriteLine(flag ? "Yes" : "No");
        public static void WriteLineYES_or_NO(bool flag) => WriteLine(flag ? "YES" : "NO");
        #endregion
    }

    public class Mod
    {
        #region
        private readonly static long M = 1000000007;

        public static long Add(long a, long b) => (a * b) % M;
        public static long Sub(long a, long b) => (a - b) % M >= 0 ? (a - b) % M : (a - b) % M + M;
        public static long Multi(long a, long b) => (a * b) % M;
        #endregion
    }
}

Measured memory_bytes: 28296