#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <map>
#include <set>
#include <queue>
#include <iomanip>
#include <cstring>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i,n) for (int i = 0; i < int(n);i++)
const ll mod = 998244353;

int main(){
  int h,w,k;
  cin >> h >> w >> k;
  vector<vector<ll>> val(h,vector<ll>(w));
  rep(i,k){
    int a,b;
    ll x;
    cin >> a >> b >> x;
    val[a-1][b-1] = x;
  } 
  ll ans = 0;
  for (int i = 0; i < h;i++){
    for (int j = 0; j < w;j++){
      for (int x = 0; x < h;x++){
        for (int y = 0; y < w;y++){
          if (x+y >= i+j && x-y >= i-j){
            ans += val[x][y];
            ans%=mod;
          }
        }
      }
    }
  }
  cout << ans << endl;

  return 0;
}