#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  int h, w, k;
  cin >> h >> w >> k;
  vector Grid(h, vector<ll>(w, 0));
  rep(_, k) {
    int x, y, v;
    cin >> x >> y >> v;
    Grid[x - 1][y - 1] = v;
  }
  ll ans = 0;
  rep(i, h) rep(j, w) {
    rep(x, h) rep(y, w) {
      if (x + y >= i + j && x - y >= i - j) ans += Grid[x][y];
    }
  }
  cout << ans % 998244353 << endl;
  return 0;
}