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 solve(n,q,arr,qq):
    lt = [0]*(n+1)
    for l,r in qq:
        lt[l-1]+=1
        lt[r]-=1
    summ = 0
    for i in range(n+1):
        summ+=lt[i]
        lt[i] = summ
    lt.sort()
    lt.reverse()
    arr.sort()
    arr.reverse()
    total = 0
    for i in range(n):
        total+=lt[i]*arr[i]
    print(total) 



txt = input()
n,q = list(map(int,txt.split(" ")))
txt = input()
arr = list(map(int,txt.split(" ")))
qq = []
for i in range(q):
    txt = input()
    ff = list(map(int,txt.split(" ")))
    qq.append(ff)


solve(n,q,arr,qq)
