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

def bulid(index,l,r,a):
  
    if l==r:
        seg[index]=a[l]
        return
    mid = math.floor((l+r)/2)
    bulid(index*2+1,l,mid,a)
    bulid(index*2+2,mid+1,r,a)
    seg[index]=seg[index*2+1]+seg[index*2+2]
    
def getvalue(index,l,r,ql,qr):
    if (l>qr) or (r<ql):
        return 99999999999
    if ql<=l and r<=qr:
        return seg[index]
    mid=math.floor((l+r)/2)
    a1=getMin(index*2+1,l,mid,ql,qr)
    a2=getMin(index*2+2,mid+1,r,ql,qr)
    return min(a1,a2)

def update(index,l,r,a,x):
    if (l>x) or (r<x):
        return 
    if x==l and r==x:
        seg[index]=a
        return
    mid=math.floor((l+r)/2)
    update(index*2+1,l,mid,a,x)
    update(index*2+2,mid+1,r,a,x)
    seg[index]=min(seg[index*2+1],seg[index*2+2])
    
l=input().split(" ")
k=int(l[0])
x=input().split(" ")
x=list(map(lambda e:int(e) ,x) )
x=sorted(x)
z=int(l[1])

indexs=[0 for i in range(k)]

que=[]
total=0

for i in range(z):
    n =input().split(" ")
    n=list(map(lambda e:int(e) ,n) )
    que.append(n)
    indexs[n[0]-1]+=1
    if n[1]<k-1:
        indexs[n[1]]-=1    
    
for i in range(1,k):
    indexs[i]=indexs[i]+indexs[i-1]

indexs=sorted(indexs)

for i in range(k):
    total+=indexs[i]*x[i]
print(total)
