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 sys

in_f = sys.stdin.read(-1).replace("\r\n", "\r")
in_f = in_f.split()

n, q = int(in_f[0]), int(in_f[1])
index_value = [[0, i] for i in range(n)]
arr = []
result = 0

for i in range(n):
    arr.append(int(in_f[i + 2]))
arr.sort()
for i in range(0, q * 2, 2):
    l, r = int(in_f[i + 2 + n]), int(in_f[i + 2 + n + 1])
    for j in range(l, r + 1):
        index_value[j - 1][0] += 1
index_value.sort()
for i in range(n):
    result += arr[i] * index_value[i][0]
print(result)
