#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
const int N = 305;
ll dp[N][N][2][2];
int n, m;
vector<int> x;
vector<int> y;
vector<int> w;
map<pii, int> mat;
int ima(int i, int j) {
return mat[{i, j}];
}
ll solve(int i, int hp, bool f1, bool f2) {
if(i == n) return 0;
ll& ret = dp[i][hp][f1][f2];
if(ret != -1) return ret;
ret = 0;
if(f2) {
for(int h = 0; h <= n; ++h) {
if(h == 0) {
ret = max(ret, solve(i + 1, 0, 0, 1));
} else {
//ret = max(ret, solve(i + 1, 0, 0, 0) + ima(i - 1, h) + ima(i + 1, h));
if(hp == h) ret = max(ret, solve(i + 1, h, 0, 0) + ima(i + 1, h));
else ret = max(ret, solve(i + 1, h, 0, 0) + ima(i + 1, h) + ima(i - 1, h));
}
}
} else {
if(!f1) {
for(int h = hp + 1; h <= n; ++h) {
ret = max(ret, solve(i + 1, h, 0, 0) + ima(i - 1, h) + ima(i + 1, h));
}
}
for(int h = hp; h >= 0; --h) {
if(h == 0) {
ret = max(ret, solve(i + 1, hp, 0, 1));
} else {
ret = max(ret, solve(i + 1, h, 1, 0) + ima(i + 1, h) - (h == hp) * ima(i, h));
}
}
}
return ret;
}
ll max_weights(int z, int d, vector<int> a, vector<int> b, vector<int> c) {
memset(dp, -1, sizeof dp);
x = a, y = b, w = c;
n = z, m = d;
for(int i = 0; i < m; ++i) mat[{x[i], y[i]}] = w[i];
return solve(0, 0, 0, 0);
}
