#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAX = 2002;
vector<pair<ll, ll>> a[MAX];
ll f[MAX][MAX], s, n, u, v, w, k, total;
void solve() {
cin >> s >> n;
for (int i = 1; i <= n; i++) {
cin >> v >> w >> k;
a[w].push_back({v, k});
}
for (int i = 1; i <= 2000; i++) sort(a[i].begin(), a[i].end(), greater<pair<ll, ll>>());
for (int i = 1; i <= s; i++) {
total = 0;
ll temp = 0;
for (auto j : a[1]) {
if (total + j.second <= i) {
total += j.second;
temp += j.second * j.first;
} else {
total += (i - total);
temp += (i - total) * j.first;
break;
}
}
f[1][i] = temp;
//cout << f[1][i] << " ";
}
//cout << "\n";
for (int i = 2; i <= s; i++) {
for (int j = 1; j <= s; j++) {
total = 0;
ll temp = 0;
f[i][j] = f[i - 1][j];
for (auto u : a[i]) {
if (total + (u.second) * i <= j) {
total += u.second * i;
temp += u.second * u.first;
} else {
total += (i - total) * i;
temp += (i - total) * u.first;
break;
}
f[i][j] = max(f[i][j], temp + f[i - 1][j - total]);
}
//cout << f[i][j] << " ";
}
//cout << "\n";
}
cout << f[s][s];
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
solve();
}
