#include <iostream>
#include <algorithm>
#include <cstring>
#include <sstream>
#include <map>
#include <queue>
#include <set>
#include <vector>
#include <stack>
#include <cstdio>
#include <cmath>
#define mk make_pair
#define pb push_back
#define printf printf_s
#define scanf scanf_s
using namespace std;
typedef long long int ll;
typedef pair<ll, ll> pos;
const ll MOD = 1000000007, N = 200010, dx[4] = { -1,1,0,0 }, dy[4] = { 0,0,-1,1 }, MIN = -72340172838076673, MAX = 72340172838076673;

ll mn(ll a, ll b) {
	if (a == -1)return b;
	if (b == -1)return a;
	return min(a, b);
}
ll gcd(ll v1, ll v2) {
	if (v1 == 0)return v2; if (v2 == 0)return v1; if (v2 > v1)return gcd(v2%v1, v1); return gcd(v1%v2, v2);
}

ll pw(ll v1, ll v2) {
	ll v3 = 1;
	while (v2 > 0) {
		if (v2 % 2)v3 = (v3*v1) % MOD;
		v1 = (v1*v1) % MOD;
		v2 /= 2;
	}
	return v3;
}

struct ab {
	ll a, b;
	bool operator<(const ab& right) const {
		return right.b*a - right.a*b < 0;
	}
};

ll n, k,a[N],sv1=0,sv2=0;
multiset<ll> st1, st2;
void ev() {
	while (st1.size() > st2.size() + 1) {
		ll v1 = *st1.begin();
		sv1 -= v1;
		st2.insert(-v1);
		sv2 += -v1;
		st1.erase(st1.begin());
	}
	while(!st2.empty()&&-*st1.begin()>*st2.begin()) {
		ll  v1 = *st1.begin(),v2=*st2.begin();
		sv1 += -v1 - v2;
		sv2 += -v1 - v2;
		st1.erase(st1.begin());
		st2.erase(st2.begin());
		st1.insert(-v2);
		st2.insert(-v1);
	}
}

void ad(ll v1) {
	st1.insert(-v1); sv1 += -v1;
	ev();
}

void dl(ll v1) {
	if (!st2.empty()&&*st2.begin() <= v1) {
		sv2 -= v1;
		st2.erase(st2.find(v1));
	}
	else {
		sv1 += v1;
		st1.erase(st1.find(-v1));
	}
	ev();
}

ll ans = -1;

int main() {
	cin >> n >> k;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
		ad(a[i]);
		if (i > k) { dl(a[i - k]); }
		if (i >= k) {
			ll v1 = -*st1.begin()*st1.size() + sv1;
			v1 += sv2 - (-*st1.begin()*st2.size());
			ans = mn(ans, v1);
		}
	}
	cout << ans << endl;
	return 0;
}