#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i, n) for(int i=0;i<(n);++i)
#define rep1(i, n) for(int i=1;i<=(n);i++)
#define ll long long
using mint = modint998244353;
using P = pair<ll,ll>;
using lb = long double;
using T = tuple<ll, ll, ll>;
#ifdef LOCAL
#  include <debug_print.hpp>
#  define dbg(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define dbg(...) (static_cast<void>(0))
#endif

int main()
{
    int h, w, k;
    cin >> h >> w >> k;
    vector<vector<ll>> v(h, vector<ll>(w));
    rep(i,k) {
        int x, y, V;
        cin >> x >> y >> V;
        --x;--y;
        v[x][y] = V;
    }
    mint ans = 0;
    rep(i,h)rep(j,w){
        rep(a,h)rep(b,w) {
            if(a+b>=i+j && a-b>=i-j) ans += v[a][b];
        }
    }
    cout << ans.val() << endl;
    return 0;
}