#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
using namespace std;
template<class T> inline void YES(T condition){ if(condition) cout << "YES" << endl; else cout << "NO" << endl; }
template<class T> inline void Yes(T condition){ if(condition) cout << "Yes" << endl; else cout << "No" << endl; }
template<class T> inline void POSS(T condition){ if(condition) cout << "POSSIBLE" << endl; else cout << "IMPOSSIBLE" << endl; }
template<class T> inline void Poss(T condition){ if(condition) cout << "Possible" << endl; else cout << "Impossible" << endl; }
template<class T> inline void First(T condition){ if(condition) cout << "First" << endl; else cout << "Second" << endl; }
template<class T = string, class U = char>int character_count(T text, U character){ int ans = 0; for(U i: text){ ans += (i == character); } return ans; }
long power(long base, long exponent, long module){ if(exponent % 2){ return power(base, exponent - 1, module) * base % module; }else if(exponent){ long root_ans = power(base, exponent / 2, module); return root_ans * root_ans % module; }else{ return 1; }}
struct position{ int y, x; }; position move_pattern[4] = {{-1, 0}, {0, 1}, {1, 0}, {0, -1}}; // double euclidean(position first, position second){ return sqrt((second.x - first.x) * (second.x - first.x) + (second.y - first.y) * (second.y - first.y)); }
template<class T, class U> string to_string(pair<T, U> x){ return to_string(x.first) + "," + to_string(x.second); }
template<class itr> void array_output(itr start, itr goal){ string ans; for(auto i = start; i != goal; i++){ ans += to_string(*i) + " "; } ans.pop_back(); cout << ans << endl; }
template<class itr> void cins(itr start, itr goal){ for(auto i = start; i != goal; i++){ cin >> (*i); } }
template<class T> T gcd(T a, T b){ if(a && b){ return gcd(min(a, b), max(a, b) % min(a, b)); }else{ return a; }} template<class T> T lcm(T a, T b){ return a / gcd(a, b) * b; }
#define mod long(1e9 + 7)
#define all(x) (x).begin(), (x).end()
#define bitcount(n) __builtin_popcountl(long(n))
#define fcout cout << fixed << setprecision(10)
#define highest(x) (63 - __builtin_clzl(x))

template<class T>
struct sum_set{
    size_t size = 0;
    long sum = 0;
    map<long, size_t, T> array;
    
    void hidden_push(long x){
        array[x]++;
    }
    
    void push(long x){
        size++;
        sum += x;
        array[x]++;
    }
    
    void pop(){
        size--;
        sum -= top();
        array[top()]--;
        if(!array[top()]){
            array.erase(top());
        }
    }
    
    void pop(long x){
        size--;
        sum -= x;
        array[x]--;
        if(!array[x]){
            array.erase(x);
        }
    }

    long top(){
        return (*array.begin()).first;
    }
};

int main(){
    int N, K;
    cin >> N >> K;
    sum_set<greater<long>> less_middle; // first (K + 1) / 2
    sum_set<less<long>> greater_middle; // last K / 2
    less_middle.hidden_push(-1e18);
    greater_middle.hidden_push(1e18);
    long A[N];
    for(int i = 0; i < K; i++){
        cin >> A[i];
        less_middle.push(A[i]);
    }
    for(int i = 0; i < K / 2; i++){
        greater_middle.push(less_middle.top());
        less_middle.pop();
    }
    long ans = (less_middle.top() * less_middle.size - less_middle.sum) + (greater_middle.sum - less_middle.top() * greater_middle.size);
    for(int i = K; i < N; i++){
        cin >> A[i];
        if(A[i - K] <= less_middle.top()){
            less_middle.pop(A[i - K]);
            long tmp[3] = {less_middle.top(), A[i], greater_middle.top()};
            less_middle.pop();
            greater_middle.pop();
            sort(tmp, tmp + 3);
            less_middle.push(tmp[0]);
            less_middle.push(tmp[1]);
            greater_middle.push(tmp[2]);
        }else{
            greater_middle.pop(A[i - K]);
            long tmp[3] = {less_middle.top(), A[i], greater_middle.top()};
            less_middle.pop();
            greater_middle.pop();
            sort(tmp, tmp + 3);
            less_middle.push(tmp[0]);
            greater_middle.push(tmp[1]);
            greater_middle.push(tmp[2]);
        }
        ans = min(ans, long(less_middle.top() * less_middle.size - less_middle.sum) + long(greater_middle.sum - less_middle.top() * greater_middle.size));
    }
    cout << ans << endl;
}