#include <bits/stdc++.h>
using namespace std;
/*
#if __has_include(<boost/multiprecision/cpp_int.hpp>)
	#include <boost/multiprecision/cpp_int.hpp>
	#include <boost/multiprecision/cpp_dec_float.hpp>
	using bll = boost::multiprecision::cpp_int;
	using bdouble = boost::multiprecision::number<boost::multiprecision::cpp_dec_float<100>>;
	using namespace boost::multiprecision;
#endif
*/
#ifdef LOCAL_TEST
	#define BOOST_STACKTRACE_USE_ADDR2LINE
	#define BOOST_STACKTRACE_ADDR2LINE_LOCATION /usr/local/opt/binutils/bin/addr2line
	#define _GNU_SOURCE 1
	#include <boost/stacktrace.hpp>
	namespace std {
		template<typename T> class dvector : public std::vector<T> {
		public:
			dvector() : std::vector<T>() {}
			explicit dvector(size_t n, const T& value = T()) : std::vector<T>(n, value) {}
			dvector(const std::vector<T>& v) : std::vector<T>(v) {}
			dvector(const std::initializer_list<T> il) : std::vector<T>(il) {}
			dvector(const std::string::iterator first, const std::string::iterator last) : std::vector<T>(first, last) {}
			dvector(const typename std::vector<T>::iterator first, const typename std::vector<T>::iterator last) : std::vector<T>(first, last) {}
			dvector(const typename std::vector<T>::reverse_iterator first, const typename std::vector<T>::reverse_iterator last) : std::vector<T>(first, last) {}
			dvector(const typename std::vector<T>::const_iterator first, const typename std::vector<T>::const_iterator last) : std::vector<T>(first, last) {}
			dvector(const typename std::vector<T>::const_reverse_iterator first, const typename std::vector<T>::const_reverse_iterator last) : std::vector<T>(first, last) {}
			T& operator[](size_t n) {
				try { return this->at(n); } catch (const std::exception& e) { std::cerr << boost::stacktrace::stacktrace() << '\n'; return this->at(n); }
			}
			const T& operator[](size_t n) const {
				try { return this->at(n); } catch (const std::exception& e) { std::cerr << boost::stacktrace::stacktrace() << '\n'; return this->at(n); }
			}
		};
	}
	class dbool {
	private:
		bool boolvalue;
	public:
		dbool() : boolvalue(false) {}
		dbool(bool b) : boolvalue(b) {}
		operator bool&() { return boolvalue; }
		operator const bool&() const { return boolvalue; }
	};
	#define vector dvector
	#define bool dbool
	class SIGFPE_exception : std::exception {};
	class SIGSEGV_exception : std::exception {};
	void catch_SIGFPE([[maybe_unused]] int e) { std::cerr << boost::stacktrace::stacktrace() << '\n'; throw SIGFPE_exception(); }
	void catch_SIGSEGV([[maybe_unused]] int e) { std::cerr << boost::stacktrace::stacktrace() << '\n'; throw SIGSEGV_exception(); }
	signed convertedmain();
	signed main() { signal(SIGFPE, catch_SIGFPE); signal(SIGSEGV, catch_SIGSEGV); return convertedmain(); }
	#define main() convertedmain()
#endif
#ifdef LOCAL_DEV
	template<typename T> std::ostream& operator<<(std::ostream& s, const std::vector<T>& v) {
		for (size_t i = 0; i < v.size(); ++i){ s << v[i]; if (i < v.size() - 1) s << "\t"; } return s; }
	template<typename T> std::ostream& operator<<(std::ostream& s, const std::vector<std::vector<T>>& vv) {
		s << "\\\n"; for (size_t i = 0; i < vv.size(); ++i){ s << vv[i] << "\n"; } return s; }
	template<typename T> std::ostream& operator<<(std::ostream& s, const std::deque<T>& v) {
		for (size_t i = 0; i < v.size(); ++i){ s << v[i]; if (i < v.size() - 1) s << "\t"; } return s; }
	template<typename T> std::ostream& operator<<(std::ostream& s, const std::set<T>& se) {
		s << "{ "; for (auto itr = se.begin(); itr != se.end(); ++itr){ s << (*itr) << "\t"; } s << "}"; return s; }
	template<typename T> std::ostream& operator<<(std::ostream& s, const std::multiset<T>& se) {
		s << "{ "; for (auto itr = se.begin(); itr != se.end(); ++itr){ s << (*itr) << "\t"; } s << "}"; return s; }
	template <typename T, size_t N> std::ostream& operator<<(std::ostream& s, const std::array<T, N>& a) {
		s << "{ "; for (size_t i = 0; i < N; ++i){ s << a[i] << "\t"; } s << "}"; return s; }
	template<typename T1, typename T2> std::ostream& operator<<(std::ostream& s, const std::map<T1, T2>& m) {
		s << "{\n"; for (auto itr = m.begin(); itr != m.end(); ++itr){ s << "\t" << (*itr).first << " : " << (*itr).second << "\n"; } s << "}"; return s; }
	template<typename T1, typename T2> std::ostream& operator<<(std::ostream& s, const std::pair<T1, T2>& p) {
		return s << "(" << p.first << ", " << p.second << ")"; }
	void debug_impl() { std::cerr << '\n'; }
	template<typename Head, typename... Tail> void debug_impl(Head head, Tail... tail) { std::cerr << " " << head << (sizeof...(tail) ? "," : ""); debug_impl(tail...); }
	#define debug(...) do { std::cerr << "(" << #__VA_ARGS__ << ") ="; debug_impl(__VA_ARGS__); } while (false)
#else
	#define debug(...) do {} while (false)
#endif
//#define int long long
using ll = long long;
//constexpr int INF = (ll)1e9 + 7;//INT_MAX=(1<<31)-1=2147483647
constexpr ll INF = (ll)1e18;//(1LL<<63)-1=9223372036854775807
constexpr ll MOD = (ll)1e9 + 7;
constexpr double EPS = 1e-9;
constexpr ll dx[4] = {1, 0, -1, 0};
constexpr ll dy[4] = {0, 1, 0, -1};
constexpr ll dx8[8] = {1, 0, -1, 0, 1, 1, -1, -1};
constexpr ll dy8[8] = {0, 1, 0, -1, 1, -1, 1, -1};
#define rep(i, n)   for(ll i=0, i##_length=(n); i< i##_length; ++i)
#define repeq(i, n) for(ll i=1, i##_length=(n); i<=i##_length; ++i)
#define rrep(i, n)   for(ll i=(n)-1; i>=0; --i)
#define rrepeq(i, n) for(ll i=(n)  ; i>=1; --i)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
void p() { std::cout << '\n'; }
template<typename Head, typename... Tail> void p(Head head, Tail... tail) { std::cout << head << (sizeof...(tail) ? " " : ""); p(tail...); }
template<typename T> inline void pv(std::vector<T>& v) { for(ll i=0, N=v.size(); i<N; i++) std::cout << v[i] << " \n"[i==N-1]; }
template<typename T> inline bool chmax(T& a, T b) { return a < b && (a = b, true); }
template<typename T> inline bool chmin(T& a, T b) { return a > b && (a = b, true); }
template<typename T> inline void uniq(std::vector<T>& v) { v.erase(std::unique(v.begin(), v.end()), v.end()); }

/*-----8<-----template-----8<-----*/
#define LOCAL_DEBUGDP
namespace debugdpdetail {
	template <typename Tp, size_t N>
	std::vector<Tp> debugdp_impl(
		ll index,
		std::vector<Tp>& dp,
		std::vector<ll>& dpitemsize,
		typename std::enable_if<(N == 1), Tp const&>::type x
	) {
		std::vector<Tp> ans(dpitemsize[1], x);
		for(ll i=0; i<dpitemsize[1]; i++) ans[i]=dp[i+index];
		return ans;
	}
	template <typename Tp, size_t N>
	auto debugdp_impl(
		ll index,
		std::vector<Tp>& dp,
		std::vector<ll>& dpitemsize,
		typename std::enable_if<(N > 1), Tp const&>::type x
	) {
		std::vector<decltype(debugdp_impl<Tp, N-1>(index, dp, dpitemsize, x))> ans;
		for(ll i=0,size=dpitemsize[N]/dpitemsize[N-1]; i<size; i++){
			ans.push_back(debugdp_impl<Tp, N-1>(index+dpitemsize[N-1]*i, dp, dpitemsize, x));
		}
		return ans;
	}
}

namespace makevectordetail {
	template <typename Tp, size_t N>
	std::vector<Tp> make_vector(
		std::vector<size_t>& sizes,
		typename std::enable_if<(N == 1), Tp const&>::type x
	) {
		return std::vector<Tp>(sizes[0], x);
	}
	template <typename Tp, size_t N>
	auto make_vector(
		std::vector<size_t>& sizes,
		typename std::enable_if<(N > 1), Tp const&>::type x
	) {
		size_t size = sizes[N-1];
		sizes.pop_back();
		return std::vector<decltype(make_vector<Tp, N-1>(sizes, x))>(
			size, make_vector<Tp, N-1>(sizes, x)
		);
	}
}
template <typename Tp, typename sizetype, size_t N>
auto make_vector(sizetype const(&sizes)[N], Tp const& x = Tp()) {
	std::vector<size_t> s(N);
	for (size_t i = 0; i < N; ++i) s[i] = sizes[N-i-1];
	return makevectordetail::make_vector<Tp, N>(s, x);
}
//vector<vector<vector<ll>>> dp = make_vector<ll>({1, 2, 3}, 0LL);
/*-----8<-----library-----8<-----*/

constexpr ll R_MAX = 3000;
constexpr ll C_MAX = 3000;
constexpr ll V_I_MAX = 1e9;

ll R, C, K;
vector<ll> r;
vector<ll> c;
vector<ll> v;

void solve() {
	cin >> R >> C >> K;
	r = vector<ll>(K);
	c = vector<ll>(K);
	v = vector<ll>(K);
	rep(i, K) { cin >> r[i] >> c[i] >> v[i];
		r[i]--,c[i]--;
	}

	vector<vector<pair<ll,ll>>> item(R);
	rep(i,K){
		item[r[i]].push_back({c[i],v[i]});
	}
	rep(i,R)sort(all(item[i]));
	//debug(item);

	using dptype = ll;
	ll dpeachsize[] = {R+1, C+1, 4};
	constexpr ll dpeacharrsize = extent<decltype(dpeachsize),0>::value;
	vector<ll> dpitemsize(dpeacharrsize+1, 1);
	for(ll i=0; i<dpeacharrsize; ++i) dpitemsize[i+1] = dpitemsize[i] * dpeachsize[dpeacharrsize-1-i];
	//vector<dptype> dp(dpitemsize.back(), 0);
	vector<vector<vector<ll>>> dp=make_vector<ll>({R+1,C+1,4LL},0LL);
	/*
	vector<bool> checked(dpitemsize.back(), false);
	auto getindex = [&](auto&&... args) {
		assert(sizeof...(args) == dpeacharrsize);
		ll ans=0, i=dpeacharrsize-1; for(auto&& n : {args...}) ans += dpitemsize[i] * n, --i; return ans;
	};
	*/
	#if defined(LOCAL_DEV) && defined(LOCAL_DEBUGDP)
		[[maybe_unused]] auto debugdp_lambda = [&](vector<dptype>& v){
			auto dp = debugdpdetail::debugdp_impl<dptype,dpeacharrsize>(0, v, dpitemsize, dptype(0)); debug(dp);
		};
		#define debugdp(v) do { debugdp_lambda(v); } while (false)
	#else
		#define debugdp(...) do {} while (false)
	#endif
	//auto f = [&](auto&& f, ll x, ll y, ll nokori) -> dptype {
	rrep(x,R)rrep(y,C)rep(nokori,4){
		if(x >= R) { dp[x][y][nokori] =0;continue; } 
		//ll dparrindex = getindex(x,y,nokori);
		//debug(x,y);
		//if(checked[dparrindex]) return dp[dparrindex];

		dptype ans = 0;

		if(nokori){
			auto it = lower_bound(all(item[x]), pair<ll,ll>(y,0), [](const pair<ll,ll> &x, const pair<ll,ll>& y) {
				return x.first < y.first;
			});
			for(;it!=item[x].end();it++){
				//ll t=f(f, x, it->first+1, nokori-1) + it->second;
				ll t=dp[x][it->first+1][nokori-1] + it->second;
				ll s=dp[x+1][it->first][3] + it->second;
				chmax(ans,t);
				chmax(ans,s);
			}

		}

		ll s=dp[x+1][y][3];
		chmax(ans,s);


		//checked[dparrindex] = true;
		//return dp[dparrindex] = ans;
		dp[x][y][nokori]=ans;
	}
	//dptype ans = f(f, 0, 0, 3);
	//debugdp(dp);
	ll ans=dp[0][0][3];
	

	//debug(f(f,1,2,2));

	cout << ans << '\n';
}

// https://atcoder.jp/contests/abc175/tasks/abc175_e
signed main() {
	std::cin.tie(nullptr);
	std::ios::sync_with_stdio(false);
	//ll Q; cin >> Q; while(Q--)solve();
	solve();
	return 0;
}


Measured memory_bytes: 646452