#include <bits/stdc++.h> 
#include <atcoder/all>
#define pub push_back
#define eb emplace_back
#define mp make_pair
#define fi first
#define se second
#define rep(i, n) rep2(i, 0, n)
#define rep2(i, m, n) for (ll i = m; i < (n); i++)
#define per(i, b) per2(i, 0, b)
#define per2(i, a, b) for (ll i = int(b) - 1; i >= int(a); i--)
#define ALL(c) (c).begin(), (c).end()
using namespace std;
using namespace atcoder;
using ll = long long; using dd = double;
using Pll = pair<ll, ll>;
using    vll = vector<   ll>; using  vdd = vector< dd>;
using   vvll = vector<  vll>; using vvdd = vector<vdd>;
using  vvvll = vector< vvll>; using vvvdd = vector<vvdd>;
using vvvvll = vector<vvvll>;
using mint = modint998244353;
using mint2 = modint1000000007;

constexpr long long INF = (1LL << 60);
constexpr double EPS = 1e-9;
constexpr double PI = 3.141592653589;

//////////////////////////////////////////////////////////

template <typename T>
bool chmax(T& a, const T& b) {
	if (a < b) {
		a = b;  // aをbで更新
		return true;
	}
	return false;
}

template <typename T>
bool chmin(T& a, const T& b) {
	if (a > b) {
		a = b;  // aをbで更新
		return true;
	}
	return false;
}

template <typename T>
T sq(T x) {
	return x * x;
}

std::string zfill(int n, const int width)
{
	std::stringstream ss;
	ss << std::setw(width) << std::setfill('0') << n;
	return ss.str();
}



int main() {
	//cout << fixed << setprecision(10);
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	ll H, W, K; cin >> H >> W >> K;
	vector<Pll> xy(K); vector<mint> v(K);
	rep(i, K) {
		cin >> xy[i].first >> xy[i].second;
		ll t; cin >> t;
		v[i] = t;
	}
	mint ans = 0;
	rep(i, H) {
		rep(j, W) {
			rep(k, K) {
				if (i + j + 2 <= xy[k].first + xy[k].second && i - j <= xy[k].first - xy[k].se) {
					ans += v[k];
				}
			}
		}
	}
	cout << ans.val() << endl;
}