#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-8;
const int maxn = 5 * 100000;
pair<pair<int, int>, int> inv[maxn];
int a[maxn], n, m;
long long s[maxn], f[maxn];
struct Node {
  int l, r;
  long long maxi, cover;
} tree[maxn * 4];
const int root = 1;
void buildTree(int l, int r, int p) {
  tree[p].l = l;
  tree[p].r = r;
  tree[p].cover = tree[p].maxi = 0;
  int mid = (l + r) >> 1;
  if (l < r) {
    buildTree(l, mid, p * 2), buildTree(mid + 1, r, p * 2 + 1);
  }
}
void down(int p) {
  tree[p * 2].cover += tree[p].cover;
  tree[p * 2 + 1].cover += tree[p].cover;
  tree[p * 2].maxi += tree[p].cover;
  tree[p * 2 + 1].maxi += tree[p].cover;
  tree[p].cover = 0;
}
void up(int p) { tree[p].maxi = max(tree[p * 2].maxi, tree[p * 2 + 1].maxi); }
void add(int l, int r, int p, long long delta) {
  if (l <= tree[p].l && r >= tree[p].r) {
    tree[p].cover += delta;
    tree[p].maxi += delta;
    return;
  }
  down(p);
  int mid = (tree[p].l + tree[p].r) >> 1;
  if (l <= mid) add(l, r, p * 2, delta);
  if (r > mid) add(l, r, p * 2 + 1, delta);
  up(p);
}
int main() {
  cin >> n >> m;
  s[0] = f[0] = 0;
  for (int i = 0; i < n; i++) cin >> s[i + 1];
  for (int i = 0; i < n; i++) s[i + 1] += s[i];
  for (int i = 0; i < m; i++)
    cin >> inv[i].first.second >> inv[i].first.first >> inv[i].second;
  sort(inv, inv + m);
  int now = 0;
  buildTree(0, n + 10, root);
  long long ans = 0;
  for (int i = 1; i <= n; ++i) {
    while (now < m && inv[now].first.first <= i) {
      add(0, --inv[now].first.second, root, inv[now].second);
      ++now;
    }
    f[i] = max(f[i - 1], tree[root].maxi - s[i]);
    ans = max(ans, f[i]);
    add(i, i, root, f[i] + s[i]);
  }
  cout << ans << endl;
  return 0;
}
