#include <iostream>
#include <vector>
using namespace std;
typedef long long ll;

ll mod = 998244353;

int main(){
    int H,W,K;
    cin >> H >> W >> K;
    vector<int> x(K);
    vector<int> y(K);
    vector<ll> v(K);
    for (int i = 0; i < K; i++){
        cin >> x[i] >> y[i] >> v[i];
        x[i]--;
        y[i]--;
    }
    ll ans = 0;

    for (int i = 0; i < H; i++){
        for (int j = 0; j < W; j++){
            for (int k = 0; k < K; k++){
                if (x[k] + y[k] >= i + j && x[k] - y[k] >= i - j){
                    ans = (ans + v[k]) % mod;
                }
            }
        }
    }
    cout << ans << endl;
}