Alice has an integer sequence a of length n and all elements are different. She will choose a subsequence of a of length m, and defines the value of a subsequence a_{b_1},a_{b_2},…,a_{b_m} as $$$∑_{i = 1}^m (m ⋅ a_{b_i}) - ∑_{i = 1}^m ∑_{j = 1}^m f(min(b_i, b_j), max(b_i, b_j)), where f(i, j) denotes \min(a_i, a_{i + 1}, \ldots, a_j)$$$.

Alice wants you to help her to maximize the value of the subsequence she choose.

A sequence s is a subsequence of a sequence t if s can be obtained from t by deletion of several (possibly, zero or all) elements.

Input

The first line contains two integers n and m (1 ≤ m ≤ n ≤ 4000).

The second line contains n distinct integers a_1, a_2, …, a_n (1 ≤ a_i < 2^{31}).

Output

Print the maximal value Alice can get.

Examples

Input


6 4
15 2 18 12 13 4


Output


100


Input


11 5
9 3 7 1 8 12 10 20 15 18 5


Output


176


Input


1 1
114514


Output


0


Input


2 1
666 888


Output


0

Note

In the first example, Alice can choose the subsequence [15, 2, 18, 13], which has the value 4 ⋅ (15 + 2 + 18 + 13) - (15 + 2 + 2 + 2) - (2 + 2 + 2 + 2) - (2 + 2 + 18 + 12) - (2 + 2 + 12 + 13) = 100. In the second example, there are a variety of subsequences with value 176, and one of them is [9, 7, 12, 20, 18].
#ifndef CPL_TEMPLATE
#define CPL_TEMPLATE
/*
	Normie's Template v2.5
	Changes:
    Added warning against using pragmas on USACO.
*/
// Standard library in one include.
#include <bits/stdc++.h>
using namespace std;
 
// ordered_set library.
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set(el) tree<el,null_type,less<el>,rb_tree_tag,tree_order_statistics_node_update>
 
// AtCoder library. (Comment out these two lines if you're not submitting in AtCoder.) (Or if you want to use it in other judges, run expander.py first.)
//#include <atcoder/all>
//using namespace atcoder;

//Pragmas (Comment out these three lines if you're submitting in szkopul or USACO.)
#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast,unroll-loops,tree-vectorize")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
 
//File I/O.
#define FILE_IN "cseq.inp"
#define FILE_OUT "cseq.out"
#define ofile freopen(FILE_IN,"r",stdin);freopen(FILE_OUT,"w",stdout)
 
//Fast I/O.
#define fio ios::sync_with_stdio(0);cin.tie(0)
#define nfio cin.tie(0)
#define endl "\n"
 
//Order checking.
#define ord(a,b,c) ((a>=b)and(b>=c))
 
//min/max redefines, so i dont have to resolve annoying compile errors.
#define min(a,b) (((a)<(b))?(a):(b))
#define max(a,b) (((a)>(b))?(a):(b))

// Fast min/max assigns to use with AVX.
// Requires g++ 9.2.0.
template<typename T>
__attribute__((always_inline)) void chkmin(T& a, const T& b) {
    a=(a<b)?a:b;
}

template<typename T>
__attribute__((always_inline)) void chkmax(T& a, const T& b) {
    a=(a>b)?a:b;
}
 
//Constants.
#define MOD (ll(998244353))
#define MAX 300001
#define mag 320
const long double PI=3.14159265358979;
 
//Pairs and 3-pairs.
#define p1 first
#define p2 second.first
#define p3 second.second
#define fi first
#define se second
#define pii(element_type) pair<element_type,element_type>
#define piii(element_type) pair<element_type,pii(element_type)>
 
//Quick power of 2.
#define pow2(x) (ll(1)<<x)
 
//Short for-loops.
#define ff(i,__,___) for(int i=__;i<=___;i++)
#define rr(i,__,___) for(int i=__;i>=___;i--)
 
//Typedefs.
#define bi BigInt
typedef long long ll;
typedef long double ld;
typedef short sh;

// Binpow and stuff
ll BOW(ll a, ll x, ll p)
{
	if (!x) return 1;
	ll res=BOW(a,x/2,p);
	res*=res;
	res%=p;
	if (x%2) res*=a;
	return res%p;
}
ll INV(ll a, ll p)
{
	return BOW(a,p-2,p);
}
//---------END-------//
#endif
vector<int> gt[4001];
int n,m,i,j,k,t,t1,u,v,a,b;
ll dp[4001][4001];
int arr[4001];
int sz[4001];
int proc(int l, int r) {
	int v=l;
	for (int i=l+1;i<=r;i++) if (arr[i]<arr[v]) {
		v=i;
	}
	if (v>l) {
		gt[v].push_back(proc(l,v-1));
	}
	if (v<r) {
		gt[v].push_back(proc(v+1,r));
	}
	return v;
}

void dfs(int x, int p, int d) {
	sz[x]=0;
	ll temp[4001];
	for (auto g : gt[x]) if (g-p) {
		dfs(g,x,arr[g]-arr[x]);
		for (int i=0;i<=sz[x]+sz[g];i++) temp[i]=0;
		for (int i=0;i<=sz[x];i++) 
		for (int j=0;j<=sz[g];j++) {
			temp[i+j]=max(temp[i+j],dp[x][i]+dp[g][j]);
		} 
		for (int i=0;i<=sz[x]+sz[g];i++) dp[x][i]=temp[i];
		sz[x]+=sz[g];
	}
	dp[x][sz[x]+1]=dp[x][sz[x]];
	for (int i=1;i<=sz[x];i++) dp[x][i]=max(dp[x][i],dp[x][i-1]);
	sz[x]++;
	for (int i=0;i<=sz[x];i++) {
		dp[x][i]+=ll(i)*(m-i)*2*d;
		// cout<<x<<' '<<i<<' '<<dp[x][i]<<endl;
	}
}

int main()
{
	fio;
	cin>>n>>m;
	for (i=1;i<=n;i++) {
		cin>>arr[i];
	}
	u=proc(1,n);
	dfs(u,-1,0);
	cout<<dp[u][m]/2;
}
// N;