#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 4000000000000000001



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