#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
//-------------------------------------------------------

template<class V, int ME> class BIT {
public:
	V bit[1<<ME],val[1<<ME];
	V operator()(int e) {if(e<0) return 0;V s=0;e++;while(e) s+=bit[e-1],e-=e&-e; return s;}
	void add(int e,V v) { val[e++]+=v; while(e<=1<<ME) bit[e-1]+=v,e+=e&-e;}
	void set(int e,V v) { add(e,v-val[e]);}
	int lower_bound(V val) {
		V tv=0; int i,ent=0;
		for(i=ME-1;i>=0;i--) if(tv+bit[ent+(1<<i)-1]<val) tv+=bit[ent+(1<<i)-1],ent+=(1<<i);
		return ent;
	}
};
BIT<ll,20> num,tot;

int N,K;
int A[101010];
int R[101010];
pair<ll,int> P[101010];

ll hoge() {
	int p=(K+1)/2;
	int x=num.lower_bound(p);
	
	ll ret=0;
	ret+=(p-1)*P[x].first-tot(x-1);
	ret+=(tot(N)-tot(x))-(K-p)*P[x].first;
	return ret;
	
}

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>N>>K;
	FOR(i,N) {
		cin>>A[i];
		P[i]={A[i],i};
	}
	sort(P,P+N);
	FOR(i,N) R[P[i].second]=i;
	
	ll mi=1LL<<60;
	FOR(i,K-1) {
		num.add(R[i],1);
		tot.add(R[i],A[i]);
	}
	for(i=0;i+K<=N;i++) {
		num.add(R[i+K-1],1);
		tot.add(R[i+K-1],A[i+K-1]);
		mi=min(mi,hoge());
		num.add(R[i],-1);
		tot.add(R[i],-A[i]);
	}
	cout<<mi<<endl;
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}