#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using mint = modint998244353;

int H, W, K;
ll A[2525][3];

int main() {
  cin >> H >> W >> K;
  for (int i = 1; i <= K; i++) {
    cin >> A[i][0] >> A[i][1] >> A[i][2];
  }
  mint ans = 0;
  for (int i = 1; i <= H; i++) {
    for (int j = 1; j <= W; j++) {
      for (int k = 1; k <= K; k++) {
        ll x = A[k][0], y = A[k][1], v = A[k][2];
        if ((x + y >= i + j) and (x - y >= i - j)) {
          ans += v;
        }
      }
    }
  }
  cout << ans.val() << endl;
  return 0;
}