Problem: There are n cities along the road, which can be represented as a straight line. The i-th city is situated at the distance of a_i kilometers from the origin. All cities are situated in the same direction from the origin. There are m trucks travelling from one city to another. 

Each truck can be described by 4 integers: starting city s_i, finishing city f_i, fuel consumption c_i and number of possible refuelings r_i. The i-th truck will spend c_i litres of fuel per one kilometer. 

When a truck arrives in some city, it can be refueled (but refueling is impossible in the middle of nowhere). The i-th truck can be refueled at most r_i times. Each refueling makes truck's gas-tank full. All trucks start with full gas-tank.

All trucks will have gas-tanks of the same size V litres. You should find minimum possible V such that all trucks can reach their destinations without refueling more times than allowed.

Input

First line contains two integers n and m (2 ≤ n ≤ 400, 1 ≤ m ≤ 250000) — the number of cities and trucks.

The second line contains n integers a_1, a_2, ..., a_n (1 ≤ a_i ≤ 10^9, a_i < a_{i+1}) — positions of cities in the ascending order.

Next m lines contains 4 integers each. The i-th line contains integers s_i, f_i, c_i, r_i (1 ≤ s_i < f_i ≤ n, 1 ≤ c_i ≤ 10^9, 0 ≤ r_i ≤ n) — the description of the i-th truck.

Output

Print the only integer — minimum possible size of gas-tanks V such that all trucks can reach their destinations.

Example

Input


7 6
2 5 7 10 14 15 17
1 3 10 0
1 7 12 7
4 5 13 3
4 7 10 1
4 7 10 1
1 5 11 2


Output


55

Note

Let's look at queries in details: 

  1. the 1-st truck must arrive at position 7 from 2 without refuelling, so it needs gas-tank of volume at least 50. 
  2. the 2-nd truck must arrive at position 17 from 2 and can be refueled at any city (if it is on the path between starting point and ending point), so it needs gas-tank of volume at least 48. 
  3. the 3-rd truck must arrive at position 14 from 10, there is no city between, so it needs gas-tank of volume at least 52. 
  4. the 4-th truck must arrive at position 17 from 10 and can be refueled only one time: it's optimal to refuel at 5-th city (position 14) so it needs gas-tank of volume at least 40. 
  5. the 5-th truck has the same description, so it also needs gas-tank of volume at least 40. 
  6. the 6-th truck must arrive at position 14 from 2 and can be refueled two times: first time in city 2 or 3 and second time in city 4 so it needs gas-tank of volume at least 55. 

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int N, M;
long long arr[405];
pair<pair<int, int>, pair<int, int>> brr[250005];
int solve(int s, int e, int c, long long t) {
  long long crnt = t;
  int ret = 0;
  for (int i = s + 1; i <= e; i++) {
    if ((arr[i] - arr[i - 1]) * c > crnt) {
      crnt = t - (arr[i] - arr[i - 1]) * c;
      ret++;
      if (crnt < 0) {
        return INT_MAX;
      }
    } else {
      crnt -= (arr[i] - arr[i - 1]) * c;
    }
  }
  return ret;
}
int main() {
  cin.sync_with_stdio(0);
  cin.tie(0);
  cin >> N >> M;
  for (int i = 1; i <= N; i++) {
    cin >> arr[i];
  }
  for (int i = 1; i <= M; i++) {
    cin >> brr[i].first.first >> brr[i].first.second >> brr[i].second.first >>
        brr[i].second.second;
  }
  random_shuffle(brr + 1, brr + 1 + M);
  long long ans = 0;
  for (int i = 1; i <= M; i++) {
    if (solve(brr[i].first.first, brr[i].first.second, brr[i].second.first,
              ans) > brr[i].second.second) {
      long long l = ans + 1, r = 2e18;
      while (l <= r) {
        long long mid = l + r >> 1;
        if (solve(brr[i].first.first, brr[i].first.second, brr[i].second.first,
                  mid) <= brr[i].second.second) {
          ans = mid;
          r = mid - 1;
        } else {
          l = mid + 1;
        }
      }
    }
  }
  cout << ans << endl;
}