#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 5;
const int mod = 1e9 + 7;
const int ub = 1e6;
long long powmod(long long x, long long y) {
  long long t;
  for (t = 1; y; y >>= 1, x = x * x % mod)
    if (y & 1) t = t * x % mod;
  return t;
}
long long gcd(long long x, long long y) { return y ? gcd(y, x % y) : x; }
long long dp[maxn];
long long tree[maxn << 2], lazy[maxn << 2];
void pushup(int l, int r, int rt) {
  tree[rt] = max(tree[rt << 1], tree[rt << 1 | 1]);
}
void pushdown(int l, int r, int rt) {
  if (lazy[rt]) {
    lazy[rt << 1] += lazy[rt];
    lazy[rt << 1 | 1] += lazy[rt];
    tree[rt << 1] += lazy[rt];
    tree[rt << 1 | 1] += lazy[rt];
    lazy[rt] = 0;
  }
}
void build(int l, int r, int rt) {
  lazy[rt] = 0;
  if (l == r) {
    tree[rt] = 0;
    return;
  }
  int mid = l + r >> 1;
  build(l, mid, rt << 1), build(mid + 1, r, rt << 1 | 1), pushup(l, r, rt);
}
void update(int l, int r, int rt, int L, int R, long long v) {
  if (L <= l && r <= R) {
    tree[rt] += v;
    lazy[rt] += v;
    return;
  }
  pushdown(l, r, rt);
  int mid = l + r >> 1;
  if (L <= mid) update(l, mid, rt << 1, L, R, v);
  if (mid < R) update(mid + 1, r, rt << 1 | 1, L, R, v);
  pushup(l, r, rt);
}
long long query(int l, int r, int rt, int L, int R) {
  if (L <= l && r <= R) {
    return tree[rt];
  }
  pushdown(l, r, rt);
  int mid = l + r >> 1;
  long long ans = 0LL;
  if (L <= mid) ans = max(ans, query(l, mid, rt << 1, L, R));
  if (mid < R) ans = max(ans, query(mid + 1, r, rt << 1 | 1, L, R));
  return ans;
}
int n, m, c[maxn];
int l, r, x;
vector<pair<int, int> > qy[maxn];
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; i++) scanf("%d", &c[i]);
  for (int i = 1; i <= m; i++) {
    scanf("%d%d%d", &l, &r, &x);
    qy[r].push_back(make_pair(l, x));
  }
  build(0, n, 1);
  for (int i = 1; i <= n; i++) {
    update(0, n, 1, 0, i - 1, -c[i]);
    if (qy[i].size()) {
      for (int j = 0; j < qy[i].size(); j++) {
        update(0, n, 1, 0, qy[i][j].first - 1, qy[i][j].second);
      }
    }
    dp[i] = max(dp[i - 1], 1LL * query(0, n, 1, 0, i - 1));
    update(0, n, 1, i, i, dp[i]);
  }
  printf("%I64d\n", max(0LL, dp[n]));
  return 0;
}
