/* -*- coding: utf-8 -*-
 *
 * 2225.cc:  No.2225 Treasure Searching Rod (Easy) - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_H = 50;
const int MAX_W = 50;
const int MAX_K = MAX_H * MAX_W;
const int MOD = 998244353;

/* typedef */

typedef long long ll;

/* global variables */

int xs[MAX_K], ys[MAX_K], vs[MAX_K];

/* subroutines */

/* main */

int main() {
  int h, w, k;
  scanf("%d%d%d", &h, &w, &k);

  for (int i = 0; i < k; i++)
    scanf("%d%d%d", xs + i, ys + i, vs + i);

  ll sum = 0;
  for (int i = 1; i <= h; i++)
    for (int j = 1; j <= w; j++)
      for (int l = 0; l < k; l++)
	if (xs[l] + ys[l] >= i + j && xs[l] - ys[l] >= i - j)
	  sum += vs[l];

  printf("%d\n", (int)(sum % MOD));
  
  return 0;
}