#include<bits/stdc++.h>
using namespace std;

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

	const long long MOD = 998244353;
	long long ans = 0;
	for( int i = 0; i < H; i++ ) {
		for( int j = 0; j < W; j++ ) {
			int p = i + j;
			int mn = i - j;
			for( int k = 0; k < H; k++ ) {
				for( int l = 0; l < W; l++ ) {
					if( k + l >= p && k - l >= mn ) ans += m[k][l];
					ans %= MOD;
				}
			}
		}
	}

	cout << ans << endl;
}