#include <cassert>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <climits>
#include <map>
#include <queue>
#include <set>
#include <cstring>
#include <vector>

using namespace std;
typedef long long ll;

const ll MOD = 998244353;

int main() {
  int H, W, K;
  cin >> H >> W >> K;

  int X[K];
  int Y[K];
  ll V[K];
  ll values[H][W];
  memset(values, 0, sizeof(values));

  for (int i = 0; i < K; ++i) {
    cin >> X[i] >> Y[i] >> V[i];
    X[i]--;
    Y[i]--;

    values[X[i]][Y[i]] = V[i];
  }

  ll ans = 0;

  for (int i = 0; i < H; ++i) {
    for (int j = 0; j < W; ++j) {
      for (int x = 0; x < H; ++x) {
        for (int y = 0; y < W; ++y) {
          if (x + y >= i + j && x - y >= i - j) {
            ans += values[x][y];
            ans %= MOD;
          }
        }
      }
    }
  }

  cout << ans << endl;

  return 0;
}