// #pragma GCC target("avx") // #pragma GCC optimize("O3") // #pragma GCC optimize("unroll-loops") #include using namespace std; #define rep(i,n) for(int i = 0; i < (int)n; i++) #define FOR(n) for(int i = 0; i < (int)n; i++) #define repi(i,a,b) for(int i = (int)a; i < (int)b; i++) #define all(x) x.begin(),x.end() //#define mp make_pair #define vi vector #define vvi vector #define vvvi vector #define vvvvi vector #define pii pair #define vpii vector> template void chmax(T &a, const T &b) {a = (a > b? a : b);} template void chmin(T &a, const T &b) {a = (a < b? a : b);} using ll = long long; using ld = long double; using ull = unsigned long long; const ll INF = numeric_limits::max() / 2; const ld pi = 3.1415926535897932384626433832795028; const ll mod = 998244353; int dx[] = {1, 0, -1, 0, -1, -1, 1, 1}; int dy[] = {0, 1, 0, -1, -1, 1, -1, 1}; #define int long long template struct Modular_Int { int x; Modular_Int() = default; Modular_Int(int x_) : x(x_ >= 0? x_%MOD : (MOD-(-x_)%MOD)%MOD) {} int val() const { return (x%MOD+MOD)%MOD; } int get_mod() const { return MOD; } Modular_Int& operator^=(int d) { Modular_Int ret(1); int nx = x; while(d) { if(d&1) ret *= nx; (nx *= nx) %= MOD; d >>= 1; } *this = ret; return *this; } Modular_Int operator^(int d) const {return Modular_Int(*this) ^= d;} Modular_Int pow(int d) const {return Modular_Int(*this) ^= d;} //use this basically Modular_Int inv() const { return Modular_Int(*this) ^ (MOD-2); } //only if the module number is not prime //Don't use. This is broken. // Modular_Int inv() const { // int a = (x%MOD+MOD)%MOD, b = MOD, u = 1, v = 0; // while(b) { // int t = a/b; // a -= t*b, swap(a, b); // u -= t*v, swap(u, v); // } // return Modular_Int(u); // } Modular_Int& operator+=(const Modular_Int other) { if((x += other.x) >= MOD) x -= MOD; return *this; } Modular_Int& operator-=(const Modular_Int other) { if((x -= other.x) < 0) x += MOD; return *this; } Modular_Int& operator*=(const Modular_Int other) { int z = x; z *= other.x; z %= MOD; x = z; if(x < 0) x += MOD; return *this; } Modular_Int& operator/=(const Modular_Int other) { return *this = *this * other.inv(); } Modular_Int& operator++() { x++; if (x == MOD) x = 0; return *this; } Modular_Int& operator--() { if (x == 0) x = MOD; x--; return *this; } Modular_Int operator+(const Modular_Int other) const {return Modular_Int(*this) += other;} Modular_Int operator-(const Modular_Int other) const {return Modular_Int(*this) -= other;} Modular_Int operator*(const Modular_Int other) const {return Modular_Int(*this) *= other;} Modular_Int operator/(const Modular_Int other) const {return Modular_Int(*this) /= other;} Modular_Int& operator+=(const int other) {Modular_Int other_(other); *this += other_; return *this;} Modular_Int& operator-=(const int other) {Modular_Int other_(other); *this -= other_; return *this;} Modular_Int& operator*=(const int other) {Modular_Int other_(other); *this *= other_; return *this;} Modular_Int& operator/=(const int other) {Modular_Int other_(other); *this /= other_; return *this;} Modular_Int operator+(const int other) const {return Modular_Int(*this) += other;} Modular_Int operator-(const int other) const {return Modular_Int(*this) -= other;} Modular_Int operator*(const int other) const {return Modular_Int(*this) *= other;} Modular_Int operator/(const int other) const {return Modular_Int(*this) /= other;} bool operator==(const Modular_Int other) const {return (*this).val() == other.val();} bool operator!=(const Modular_Int other) const {return (*this).val() != other.val();} bool operator==(const int other) const {return (*this).val() == other;} bool operator!=(const int other) const {return (*this).val() != other;} Modular_Int operator-() const {return Modular_Int(0LL)-Modular_Int(*this);} //入れ子にしたい // friend constexpr istream& operator>>(istream& is, mint& x) noexcept { // int X; // is >> X; // x = X; // return is; // } // friend constexpr ostream& operator<<(ostream& os, mint& x) { // os << x.val(); // return os; // } }; // const int MOD_VAL = 1e9+7; const int MOD_VAL = 998244353; using mint = Modular_Int; istream& operator>>(istream& is, mint& x) { int X; is >> X; x = X; return is; } ostream& operator<<(ostream& os, mint& x) { os << x.val(); return os; } // istream& operator<<(istream& is, mint &a) { // int x; // is >> x; // a = mint(x); // return is; // } // ostream& operator<<(ostream& os, mint a) { // os << a.val(); // return os; // } // vector f = {1}, rf = {1}; // void init(int n) { // f.resize(n, 0); // rf.resize(n, 0); // f[0] = 1; // repi(i, 1, n) f[i] = (f[i - 1] * i); // repi(i, 0, n) rf[i] = f[i].inv(); // } // mint P(int n, int k) { // assert(n>=k); // while(n > f.size()-1) { // f.push_back(f.back() * f.size()); // rf.push_back(f.back().inv()); // } // return f[n] * f[n-k]; // } // mint C(int n, int k) { // assert(n>=k); // while(n > f.size()-1) { // f.push_back(f.back() * f.size()); // rf.push_back(f.back().inv()); // } // return f[n]*rf[n-k]*rf[k]; // } // mint H(int n, int k) { // assert(n>=1); // return C(n+k-1, k); // } // mint Cat(int n) { // return C(2*n, n)-C(2*n, n-1); // } void solve() { int h, w, k; cin >> h >> w >> k; mint ans = 0; FOR(k) { int x, y, v; cin >> x >> y >> v; auto cal = [&](int X, int Y) -> mint { int N = min(X, Y); int M = max(0LL, X - Y); return mint(N)*(N+1)/2 + M*Y; }; mint many = cal(x, w-y+1) + cal(x, y) - x; ans += many * v; // int X = h - x + 1; // int Y = w - y + 1; // int N1 = min(X, Y); // int M1 = max(0LL, X - Y); // mint up = mint(N1)*(N1+1)/2 + mint(M1) * Y; // int N2 = min(X, y); // int M2 = max(0LL, X - y); // mint lo = mint(N2)*(N2+1)/2 + mint(M2) * y; // ans += mint(h)*w*v; // ans -= (up + lo - ) * v; } cout << ans.val() << endl; } signed main() { cin.tie(nullptr); ios::sync_with_stdio(false); solve(); return 0; }