#include <bits/stdc++.h>
#include <atcoder/all>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rrep(i, n, m) for (int i = (int)(n); i > (int)(m); i--)
#define rep1(i, n, m) for (int i = (int)(n); i < (int)(m); i++)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend() using namespace atcoder;
using ll = long long;
const ll MOD1 = 1000000007LL;
const ll MOD2 = 998244353LL;
using namespace std;
using namespace atcoder;
const vector<pair<int, int>> dpos4 = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
// const vector<pair<int, int>> dpos8 = {{-1, -1}, {-1, 0}, {-1, 1}, {0, -1}, {0, 1}, {1, -1}, {1, 0}, {1, 1}};
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 pow(T a, ll b){
    if(b == 0) return 1;
    if(b % 2 == 0) return pow(a / 2, b / 2);
    return a * pow(a, b - 1);
}

using mint = modint998244353;
int main() {
    int H, W, K;
    cin >> H >> W >> K;
    vector<vector<mint>> treasures(H, vector<mint>(W, 0));
    rep(i, K){
        int a, b; ll c;
        cin >> a >> b >> c;
        a--, b--;
        treasures[a][b] += c;
    }

    mint ans = 0;
    rep(h, H) rep(w, W) rep(i, H) rep(j, W){
        if(i + j >= h + w && i - j >= h - w){
            ans += treasures[i][j];
        }
    }
    cout << ans.val() << endl;
	return 0;
}