#include <bits/stdc++.h>
#include <climits>
#include <deque>
#include <ostream>
#include <queue>
using namespace std;

int main() {
	int n,k;
	cin >> n >> k;

	deque<int> tomb;
	int max=0, hely, vegszamlalo=INT_MAX;
	for(int i=0;i<k-1;i++){
		int valt;
		cin >> valt;
		if(valt>max){
			max=valt;
			hely=i;
		}
		tomb.push_back(valt);
		cerr << valt;
	}
	for(int i=k-1;i<n;i++){
		
		cerr << endl;
		int valt, szamlalo=0;
		cin >> valt;
		tomb.push_back(valt);

		priority_queue<pair<int,int>> pq;

		for(int i=0;i<tomb.size();i++){
			pq.push(make_pair(tomb[i],i));
			cerr << tomb[i] << " ";
		}

		max=pq.top().first;
		hely=pq.top().second;

		cerr <<endl << max << " " << hely << " ";
		for(int x=0;x<=hely;x++){

			szamlalo+=abs(tomb[x]-max)+hely-x;
			cerr << szamlalo << endl;
		}
		for(int x=hely+1;x<k;x++){
			szamlalo+=max-tomb[x]+hely-x;
			cerr << x << " " << szamlalo << endl;
		}
		if(szamlalo<vegszamlalo){
			vegszamlalo=szamlalo;
		}
		tomb.pop_front();
	}
	cout << vegszamlalo;
}