#include <bits/stdc++.h>
using namespace std;
using ll=long long;
const ll mod=998244353;
int main() {
    ll H,W,K;
    cin>>H>>W>>K;
    vector<vector<ll>> S(H,vector<ll>(W,0));
    for(ll k=0;k<K;k++){
        ll X,Y,V;
        cin>>X>>Y>>V;
        S[X-1][Y-1]+=V;
    }
    ll an=0;
    for(ll x=0;x<H;x++)for(ll y=0;y<W;y++){
        for(ll i=0;i<H;i++)for(ll j=0;j<W;j++){
            if(x+y>=i+j&&x-y>=i-j)an=(an+S[x][y])%mod;
        }
    }
    cout<<an<<endl;
}