using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        var input = Console.ReadLine().Split().Select(int.Parse).ToArray();
        var H = input[0];
        var W = input[1];
        var K = (long)input[2];
        var sum = 0L;
        var treasure = new Dictionary<(int, int), long>();

        for (int i = 0; i < K; i++)
        {
            var temp = Console.ReadLine().Split().Select(int.Parse).ToArray();
            temp[0]--;
            temp[1]--;
            treasure.Add((temp[0], temp[1]), temp[2]);
        }

        var dic = new Dictionary<(int, int), int>();

        for (int i = 0; i < H; i++)
        {
            for (int j = 0; j < W; j++)
            {
                for (int x = i; x < H; x++)
                {
                    for (int y = j - (H - i) < 0 ? 0 : j - (H - i); y < (j + (H - i) > W - 1 ? W : j + (H - i)); y++)
                    {
                        if ((x + y >= i + j) && (x - y >= i - j))
                        {
                            if (dic.ContainsKey((x, y))) dic[(x, y)]++;
                            else dic.Add((x, y), 1);
                        }
                    }
                }
            }
        }

        foreach (var item in treasure)
        {
            if (dic.ContainsKey(item.Key)) sum += dic[item.Key] * item.Value;
        }

        Console.WriteLine(sum % 998244353);
    }
}