#include <bits/stdc++.h>
using namespace std;
using i32 = int;
using i64 = long long;
template <typename T>
using V = vector<T>;
template <typename T>
using VV = V<V<T>>;
template <typename T>
using VVV = V<V<V<T>>>;
template <typename T>
bool chmin(T &x, const T &y) {
if (x > y) {
x = y;
return true;
}
return false;
}
template <typename T>
bool chmax(T &x, const T &y) {
if (x < y) {
x = y;
return true;
}
return false;
}
#define OVERRIDE4(a, b, c, d, ...) d
#define REP2(i, n) for (i32 i = 0; i < (i32)(n); ++i)
#define REP3(i, l, r) for (i32 i = (i32)(l); i < (i32)(r); ++i)
#define REP(...) OVERRIDE4(__VA_ARGS__, REP3, REP2)(__VA_ARGS__)
#define PER2(i, n) for (i32 i = (i32)(n)-1; i >= 0; --i)
#define PER3(i, l, r) for (i32 i = (i32)(r)-1; i >= (i32)(l); --i)
#define PER(...) OVERRIDE4(__VA_ARGS__, PER3, PER2)(__VA_ARGS__)
#define ALL(x) begin(x), end(x)
#define LEN(x) (i32) size(x)
void dbg(i32 x) { cerr << x; }
void dbg(i64 x) { cerr << x; }
template <typename T, typename U>
void dbg(pair<T, U> p) {
cerr << '(' << p.first << ", " << p.second << ')';
}
template <typename T>
void dbg(V<T> arr) {
cerr << '[';
REP(i, LEN(arr)) {
if (i) {
cerr << ", ";
}
dbg(arr[i]);
}
cerr << ']';
}
void debug() { cerr << '\n'; }
template <typename Head, typename... Tail>
void debug(Head head, Tail... tail) {
dbg(head);
cerr << ", ";
debug(tail...);
}
#ifdef DEBUGF
#define DBG(...) \
do { \
cerr << #__VA_ARGS__ << " : "; \
debug(__VA_ARGS__); \
} while (false)
#else
#define DBG(...) (void)0
#endif
#include "fish.h"
constexpr i64 INF = 3003003003003003003;
long long max_weights(i32 n, i32 m, V<i32> x, V<i32> y, V<i32> w) {
VV<pair<i32, i64>> wts(n);
REP(i, m) {
wts[x[i]].emplace_back(y[i], w[i]);
}
REP(i, n) {
sort(ALL(wts[i]));
}
V<i64> mxr(n + 1, 0);
VV<i64> up(n), down(n);
REP(i, n) {
up[i].resize(LEN(wts[i]), -INF);
down[i].resize(LEN(wts[i]), -INF);
}
REP(i, LEN(wts[0])) {
up[0][i] = wts[0][i].second;
}
REP(i, n) {
if (i > 0) {
REP(j, LEN(wts[i])) {
chmax(up[i][j], mxr[i - 1] + wts[i][j].second);
chmax(down[i][j], mxr[i - 1] + wts[i][j].second);
{
auto itr = lower_bound(ALL(wts[i - 1]), pair<i32, i64>(wts[i][j].first, 0LL));
if (itr != begin(wts[i - 1])) {
i32 idx = itr - begin(wts[i - 1]) - 1;
chmax(up[i][j], up[i - 1][idx] + wts[i][j].second);
}
}
{
auto itr = lower_bound(ALL(wts[i - 1]), pair<i32, i64>(wts[i][j].first + 1, 0LL));
if (itr != end(wts[i - 1])) {
i32 idx = itr - begin(wts[i - 1]);
chmax(down[i][j], down[i - 1][idx] + wts[i][j].second);
}
}
}
i64 pmax = -INF;
REP(j, LEN(wts[i - 1])) {
chmax(pmax, down[i - 1][j]);
}
REP(j, LEN(wts[i])) {
chmax(up[i][j], pmax + wts[i][j].second);
}
}
PER(j, LEN(wts[i]) - 1) {
chmax(down[i][j], down[i][j + 1] + wts[i][j].second);
}
REP(j, 1, LEN(wts[i])) {
chmax(up[i][j], up[i][j - 1] + wts[i][j].second);
}
chmax(mxr[i + 1], mxr[i]);
REP(j, LEN(wts[i])) {
chmax(mxr[i + 1], up[i][j]);
chmax(mxr[i + 1], down[i][j]);
}
}
i64 ans = mxr[n - 1];
REP(i, LEN(wts[n - 1])) {
chmax(ans, down[n - 1][i]);
}
return ans;
}
