The little girl loves the problems on array queries very much.

One day she came across a rather well-known problem: you've got an array of $n$ elements (the elements of the array are indexed starting from 1); also, there are $q$ queries, each one is defined by a pair of integers $l_i$, $r_i$ $(1 \le l_i \le r_i \le n)$. You need to find for each query the sum of elements of the array with indexes from $l_i$ to $r_i$, inclusive.

The little girl found the problem rather boring. She decided to reorder the array elements before replying to the queries in a way that makes the sum of query replies maximum possible. Your task is to find the value of this maximum sum.
The first line contains two space-separated integers $n$ ($1 \le n \le 2\cdot10^5$) and $q$ ($1 \le q \le 2\cdot10^5$) — the number of elements in the array and the number of queries, correspondingly.

The next line contains $n$ space-separated integers $a_i$ ($1 \le a_i \le 2\cdot10^5$) — the array elements.

Each of the following $q$ lines contains two space-separated integers $l_i$ and $r_i$ ($1 \le l_i \le r_i \le n$) — the $i$-th query.
def findQueries(nums, queries):
    length = len(nums)
    prefix = [0] * (length + 1)
    for x, y in queries:
        prefix[x - 1] += 1
        prefix[y] -= 1
    sumVal = 0
    temp = []
    for i in range(length):
        sumVal += prefix[i]
        prefix[i] = sumVal
        temp.append([prefix[i], i])
    nums.sort()
    temp.sort()
    for i in range(length):
        temp[i][0] = nums[i]
    temp.sort(key=lambda x:x[1])

    prefixSum = [0]
    for x, y in temp:
        prefixSum.append(prefixSum[-1] + x)

    res = 0
    for x, y in queries:
        res += (prefixSum[y] - prefixSum[x - 1])

    return res

m, n = list(map(int, input().split(" ")))
arr = list(map(int, input().split(" ")))
q = []
for i in range(n):
    q.append(list(map(int, input().split(" "))))
print(findQueries(arr, q))
