#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <cmath>
#include <iomanip>
#include <stack>
#include <queue>
#include <numeric>
#include <map>
#include <unordered_map>
#include <set>
#include <fstream>
#include <chrono>
#include <random>
#include <bitset>
//#include <atcoder/all>
#define rep(i,n) for(int i=0;i<(n);i++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) ((int)(x).size())
#define pb push_back
using ll = long long;
using namespace std;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
ll gcd(ll a, ll b) {return b?gcd(b,a%b):a;}
ll lcm(ll a, ll b) {return a/gcd(a,b)*b;}

int main(){
  const ll mod = 998244353;
  int H,W,K; cin >> H >> W >> K;
  vector<vector<ll>> A(H,vector<ll>(W,0));
  rep(i,K){
    int y,x; ll v; cin >> y >> x >> v; y--; x--;
    A[y][x] = v;
  }
  ll ans = 0;
  rep(y,H){
    rep(x,W){
      rep(yy,H){
        rep(xx,W){
          if(yy+xx>=y+x&&yy-xx>=y-x){
            ans += A[yy][xx];
            ans %= mod;
          }
        }
      }
    }
  }
  cout << ans << endl;
  return 0;
}