#include <bits/stdc++.h>
using namespace std;
const int N = 200050;
const int M = 2 * N;
const long long inf = 9e18;
vector<int> ids[N];
int a[N], l[N], r[N], p[N];
long long dp[N];
int ls[M], rs[M], tsz, root;
long long mx[M], lzy[M];
void Build(int &c, int ss, int se) {
  c = ++tsz;
  mx[c] = lzy[c] = 0;
  if (ss == se) return;
  int mid = ss + se >> 1;
  Build(ls[c], ss, mid);
  Build(rs[c], mid + 1, se);
}
void Push(int c, int ss, int se) {
  if (!lzy[c]) return;
  if (ss != se) {
    mx[ls[c]] += lzy[c];
    lzy[ls[c]] += lzy[c];
    mx[rs[c]] += lzy[c];
    lzy[rs[c]] += lzy[c];
  }
  lzy[c] = 0;
}
void Inc(int c, int ss, int se, int qs, int qe, long long f) {
  if (qs > se || ss > qe || qs > qe) return;
  if (qs <= ss && qe >= se) {
    mx[c] += f;
    lzy[c] += f;
    return;
  }
  int mid = ss + se >> 1;
  Push(c, ss, se);
  Inc(ls[c], ss, mid, qs, qe, f);
  Inc(rs[c], mid + 1, se, qs, qe, f);
  mx[c] = max(mx[ls[c]], mx[rs[c]]);
}
long long Get(int c, int ss, int se, int qs, int qe) {
  if (qs > se || ss > qe || qs > qe) return -inf;
  if (qs <= ss && qe >= se) return mx[c];
  Push(c, ss, se);
  int mid = ss + se >> 1;
  return max(Get(ls[c], ss, mid, qs, qe), Get(rs[c], mid + 1, se, qs, qe));
}
int main() {
  int n, m, i;
  scanf("%i %i", &n, &m);
  for (i = 1; i <= n; i++) scanf("%i", &a[i]);
  for (i = 1; i <= m; i++)
    scanf("%i %i %i", &l[i], &r[i], &p[i]), ids[r[i]].push_back(i);
  Build(root, 1, n);
  for (i = 1; i <= n; i++) {
    Inc(root, 1, n, 1, i, -a[i]);
    Inc(root, 1, n, i, i, dp[i - 1]);
    for (int j : ids[i]) Inc(root, 1, n, 1, l[j], p[j]);
    dp[i] = max(Get(root, 1, n, 1, i), dp[i - 1]);
  }
  printf("%lld\n", dp[n]);
  return 0;
}
