#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(),(x).end()
#define fix(x) fixed << setprecision(x)
#define eb emplace_back
constexpr char nl='\n';
using namespace std;
using ll = long long;
using ld = long double;
using vl = vector<long long>;
using vvl = vector<vector<long long>>;
using vs = vector<string>;
using pl = pair<long long, long long>;
template <typename T> inline bool chmin(T& a, const T& b) {bool compare = a > b; if (a > b) a = b; return compare;}
template <typename T> inline bool chmax(T& a, const T& b) {bool compare = a < b; if (a < b) a = b; return compare;}
template<class T>using rp_queue=priority_queue<T,vector<T>,greater<T>>;
void fast_io(){cin.tie(nullptr);ios_base::sync_with_stdio(false);}
template <typename T> T gcd(T a, T b) {if (b == 0)return a; else return gcd(b, a % b);}
template <typename T> inline T lcm(T a, T b) {return a /gcd(a, b)*b;}
const ll INF = 1LL << 60;
const ld PI = acos(-1);
const ll mod = 998244353;
void solve(){
  int H,W,K;cin>>H>>W>>K;
  vvl cnt(H,vl(W,-1));
  rep(i,K){
    int x,y;
    ll k;cin>>x>>y>>k;
    x--;
    y--;
    cnt[x][y] = k;
  }
  ll ans = 0;
  rep(x,H){
    rep(y,W){
      rep(i,H){
        rep(j,W){
          if(x+y>=i+j&&x-y>=i-j){
            if(cnt[x][y]!=-1){
              ans+=cnt[x][y];
              ans%=mod;
            }
          }
        }
      }
    }
  }
  cout<<ans<<endl;
}
int main(){
  fast_io();
  int num_tc = 1;
  //cin >> num_tc;
  rep(tc,num_tc){
    //cout << "Case #" << tc+1 << ": " ;// << endl;
    solve();
  }
}