#include<bits/stdc++.h>
using namespace std;
#define ALL(x) begin(x),end(x)
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define mod 1000000007
using ll=long long;
const int INF=1000000000;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
// ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

struct IOSetup{
    IOSetup(){
        cin.tie(0);
        ios::sync_with_stdio(0);
        cout<<fixed<<setprecision(12);
    }
} iosetup;
 
template<typename T>
ostream &operator<<(ostream &os,const vector<T>&v){
    for(int i=0;i<(int)v.size();i++) os<<v[i]<<(i+1==(int)v.size()?"":" ");
    return os;
}
template<typename T>
istream &operator>>(istream &is,vector<T>&v){
    for(T &x:v)is>>x;
    return is;
}


signed main(){
    int n,k;cin>>n>>k;
    vector<ll> a(n);
    cin>>a;

    multiset<ll> le,ri;
    ll les=0,ris=0;

    auto flatten=[&](){
        while(ri.size()<le.size()){
            ll x=*prev(le.end());
            le.erase(prev(le.end()));
            ri.insert(x);
            les-=x;
            ris+=x;
        }
        while(ri.size()>le.size()){
            ll x=*ri.begin();
            ri.erase(ri.begin());
            le.insert(x);
            ris-=x;
            les+=x;
        }
    };

    auto f=[&](){
        ll med=*prev(le.end());
        ll ret=0;
        {
            ll sz=(ll)le.size();
            ret+=sz*med-les;
        }
        {
            ll sz=(ll)ri.size();
            ret+=ris-sz*med;
        }
        return ret;
    };

    rep(i,k){
        le.insert(a[i]);
        les+=a[i];
    }
    flatten();
    ll res=f();

    for(int i=k;i<n;i++){
        if(*ri.begin()<=a[i]){
            ri.insert(a[i]);
            ris+=a[i];
        }else{
            le.insert(a[i]);
            les+=a[i];
        }

        ll er=a[i-k];
        if(le.find(er)!=le.end()){
            le.erase(le.find(er));
            les-=er;
        }else{
            ri.erase(ri.find(er));
            ris-=er;
        }

        flatten();
        chmin(res,f());
    }
    cout<<res<<endl;
    return 0;
}