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.
import math
import bisect

ipt = input().split()

n = int(ipt[0])
q = int(ipt[1])

ipt = input().split()

a = list(map(int, ipt))

starting  = [0]* n
ending = [0]*n

for i in range(q):
    ipt = input().split()
    s = int(ipt[0])
    e =  int(ipt[1])
    
    starting[s-1] += 1
    ending[e-1] += 1 
    
# print(starting)
# print(ending)


index = [0]*n
x = 0
for i in range(n):
    x = x +  starting[i]
    index[i] = x
    x = x - ending[i]
    
#print(index)    
    

index.sort()
a.sort()


cnt  = 0
for i in range(n):
    cnt += a[i] * index[i]
    
print(cnt)








    
    
    
    