#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/dsu>
#include <atcoder/modint>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define modulo 1000000007
#define mod(mod_x) ((((long long)mod_x+modulo))%modulo)
#define Inf 1000000000000000000
int N,K;
vector<long long> A;

long long f(long long x){
	deque<long long> D0,D1;
	rep(i,N){
		if(i<K)D0.push_back(A[i]);
		else D1.push_back(A[i]);
	}
	
	long long mini = Inf;
	long long cur = 0LL;
	rep(i,N){
		if(A[i]<=x)cur -= x;
		else cur += x;
	}
	rep(i,D0.size()){
		if(D0[i]<=x){
			cur -= D0[i];
			cur += x*2;
		}
		else{
			cur += D0[i];
			cur -= x*2;
		}
	}
	rep(i,D1.size()){
		if(D1[i]<=x){
			cur += D1[i];
		}
		else{
			cur -= D1[i];
		}
	}
	mini = cur;
	
	rep(i,N){
		long long A = D0.front();
		D0.pop_front();
		if(A<=x){
			cur += A;
			cur -= x*2;
			cur += A;
		}
		else{
			cur -= A;
			cur += x*2;
			cur -= A;
		}
		D1.push_back(A);
		
		A = D1.front();
		D1.pop_front();
		
		if(A<=x){
			cur -= A;
			cur -= A;
			cur += x*2;
		}
		else{
			cur += A;
			cur += A;
			cur -= x*2;
		}
		
		mini = min(mini,cur);
		
		
	}
	//if(mini==-89)cout<<x<<endl;
	return mini;
}

int main(){
	
	cin>>N>>K;
	A.resize(N);
	rep(i,N){
		scanf("%lld",&A[i]);
	}
	if(K==0){
		long long ans = 0LL;
		rep(i,N){
			ans += A[i]-A[0];
		}
		cout<<-ans<<endl;
		return 0;
	}
	
	
	long long ans = f(A[0]);
	ans = min(ans,f(A.back()));
	ans = min(ans,f((A[0]+A.back())/2));
	ans = min(ans,f((min(A.back(),A[0]+A.back())/2+1)));
	
	cout<<ans<<endl;
	
	return 0;
}