using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Collections.Specialized;
using System.Linq;
using System.Numerics;

namespace AtCoderWorkspace
{
    public class Solver
    {
        public void Solve()
        {
            var cin = new Scanner();
            var n = cin.nextInt();
            var m = cin.nextInt();
            var q = cin.nextInt();
            var list = new List<Quad>();

            for (int i = 0; i < q; i++)
            {
                var a = cin.nextInt()-1;
                var b = cin.nextInt()-1;
                var c = cin.nextInt();
                var d = cin.nextInt();

                var ll = new Quad() { a = a, b = b, c = c, d = d };
                list.Add(ll);
            }

            // permutation
            var now = new List<ImmutableArray<int>>();
            for (int i = 1; i <= m; i++)
            {
                now.Add(ImmutableArray.Create(i));
            }
            for (int i = 1; i < n; ++i)
            {
                var next = new List<ImmutableArray<int>>();
                foreach (var x in now)
                {
                    for (int j = x.Last(); j <= m; ++j) next.Add(x.Add(j));
                }
                now = next;
            }

            var ans = 0L;
            foreach (var item in now)
            {
                var sum = 0L;
                foreach (var quad in list)
                {
                    if (item[quad.b] - item[quad.a] == quad.c) sum += quad.d;
                }
                ans = Math.Max(ans, sum);
            }

            Console.WriteLine(ans);
        }
    }

    class Quad
    {
        public int a { get; set; }
        public int b { get; set; }
        public int c { get; set; }
        public int d { get; set; }
    }

    class Scanner
    {
        string[] s;
        int i;

        char[] cs = new char[] { ' ' };

        public Scanner()
        {
            s = new string[0];
            i = 0;
        }

        public string next()
        {
            if (i < s.Length) return s[i++];
            string st = Console.ReadLine();
            while (st == "") st = Console.ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            if (s.Length == 0) return next();
            i = 0;
            return s[i++];
        }

        public int nextInt()
        {
            return int.Parse(next());
        }
        public int[] ArrayInt(int N, int add = 0)
        {
            int[] Array = new int[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextInt() + add;
            }
            return Array;
        }

        public int[] DPArrayInt(int N, int ex)
        {
            int[] Array = new int[N + ex];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextInt();
            }
            return Array;
        }

        public long nextLong()
        {
            return long.Parse(next());
        }

        public long[] ArrayLong(int N, long add = 0)
        {
            long[] Array = new long[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextLong() + add;
            }
            return Array;
        }

        public long[] DPArrayLong(int N, int ex)
        {
            long[] Array = new long[N + ex];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextLong();
            }
            return Array;
        }

        public double nextDouble()
        {
            return double.Parse(next());
        }


        public double[] ArrayDouble(int N, double add = 0)
        {
            double[] Array = new double[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextDouble() + add;
            }
            return Array;
        }
    }

    class Program
    {
        static void Main(string[] s) => new Solver().Solve();
    }
}


Measured memory_bytes: 43356