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 main():
	n, q = list(map(int, input().strip().split()))
	a = list(map(int, input().strip().split()))
	a.sort(reverse = True)
	val = [0]*200100
	b = [0]*200100
	for i in range(q):
		li, ri = list(map(int, input().strip().split()))
		li -= 1
		ri -= 1
		val[li] += 1
		val[ri+1] -= 1
	# print(val[:n+1])
	v = 0
	for i in range(n):
		# print("v: ", v, "val[i]:", val[i])
		v += val[i]
		b[i] = v
		# print(b[i])
	b.sort(reverse = True)
	# print(b[:n+1])
	res = 0
	for i in range(n):
		res += b[i]*a[i]

	print(str(res))




# def main():
# 	n, q = list(map(int, input().strip().split()))
# 	a = list(map(int, input().strip().split()))
# 	queries = []
# 	array = [0]*(n+1)
# 	for i in range(q):
# 		li, ri = list(map(int, input().strip().split()))
# 		for i in range(li, ri+1):
# 			array[i] += 1

# 	a.sort(reverse = True)
# 	array.sort(reverse = True)
# 	solution = 0
# 	for i in range(0, n):
# 		solution += (a[i]*array[i])

# 	print(str(solution))

if __name__ == '__main__':
	main()