CodeForces - 276C Little Girl and Maximum Sum （扫描线）

题意：

        有若干对区间和的查询，问如何重组数组使查询结果的和最大。N为区间长度，M为查询次数。

思路：

        统计出每一个位置出现的次数，统计的过程利用扫描线，然后当然出现最多的那个位置放最大的数，然后相乘累加就行

代码：

#include <bits/stdc++.h>using namespace std;const int MAXN=2e5+100;long long a[MAXN];long long lis[MAXN];int main(){    ios::sync_with_stdio(false);    long long n,m,st,en;    while(cin>>n>>m){        memset(lis,0,sizeof(lis));        for(int i=0;i<n;i++)            cin>>a[i];        sort(a,a+n);        while(m--){            cin>>st>>en;            lis[st-1]++;            lis[en]--;        }        for(int i=1;i<n;i++)            lis[i]+=lis[i-1];        sort(lis,lis+n);        long long ans=0;        for(int i=0;i<n;i++)            ans+=lis[i]*a[i];        cout<<ans<<endl;    }}

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 nelements (the elements of the array are indexed starting from 1); also, there are qqueries, each one is defined by a pair of integers l_i, r_i (1 ≤ l_i ≤ r_i ≤ 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.

Input

The first line contains two space-separated integers n (1 ≤ n ≤ 2·10⁵) and q (1 ≤ q ≤ 2·10⁵) — the number of elements in the array and the number of queries, correspondingly.

The next line contains n space-separated integers a_i (1 ≤ a_i ≤ 2·10⁵) — the array elements.

Each of the following q lines contains two space-separated integers l_i and r_i (1 ≤ l_i ≤ r_i ≤ n) — the i-th query.

Output

In a single line print a single integer — the maximum sum of query replies after the array elements are reordered.

Please, do not use the %lld specifier to read or write 64-bit integers in С++. It is preferred to use the cin, cout streams or the %I64d specifier.

Example

Input

3 35 3 21 22 31 3

Output

25

Input

5 35 2 4 1 31 52 32 3

Output

33