#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define fi first
#define se second
#define pii pair<int, int>
#define pb push_back
#define vi vector<int>
#define all(x) x.begin(), x.end()
using namespace std;
using namespace __gnu_pbds;
using ll = long long int;
using ull = unsigned long long int;
constexpr ll mod = 1e9 + 7;
constexpr ll INF = LONG_LONG_MAX;
int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, 1, 0, -1};
string moves = "URDL";
int main()
{
//tree<ll, null_type,less<ll>, rb_tree_tag,tree_order_statistics_node_update> q;
/*freopen("problemname.in", "r", stdin);
freopen("problemname.out", "w", stdout);*/
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
ll x, n, ans = 0, a, b, c;
cin >> x >> n;
vector<pair<ll, ll>> arr[x + 1];
for(ll i = 0;i<n;++i) {
cin >> a >> b >> c;
arr[b].pb({a, c});
}
for(ll i = 0;i<=x;++i) {
sort(all(arr[i]), greater<pair<ll, ll>>());
}
vector<ll> rel[x + 1];
for(ll i = 0;i<=x;++i) {
for(pair<ll, ll>& v:arr[i]) {
if ((ll)rel[i].size() + v.se <= 2*x) {
for(ll j = 0;j<v.se;++j) {
rel[i].pb(v.fi);
}
}
else {
for(ll j = 0;j<2*x - (ll)rel[i].size();++j) {
rel[i].pb(v.fi);
}
break;
}
}
}
ll dp[x + 1][x + 1];
memset(dp, 0, sizeof dp);
for(ll i = 1;i<=x;++i) {
for(ll j = 0;j<=x;++j) {
dp[i][j] = max(dp[i][j], dp[i - 1][j]);
ll cnt = 1, val = 0, siz = rel[i].size();
while(j - cnt*i >= 0 && cnt <= siz) {
val+=rel[i].at(cnt - 1);
dp[i][j] = max(dp[i][j], dp[i - 1][j - cnt*i] + val);
++cnt;
}
ans = max(ans, dp[i][j]);
}
}
cout << ans << endl;
return 0;
}
