#include<bits/stdc++.h>
using namespace std;
using Int = long long;

struct FullyIndexableDictionary{
  Int len,blk;
  vector<Int> bit,sum;
  
  FullyIndexableDictionary(){}
  FullyIndexableDictionary(Int len)
    :len(len),blk((len+31)>>5),bit(blk,0),sum(blk,0){}
  
  void set(Int k){
    bit[k>>5]|=1<<(k&31);
  }

  void build(){
    sum[0]=0;
    for(Int i=1;i<blk;i++)
      sum[i]=sum[i-1]+__builtin_popcount(bit[i-1]);
  }

  bool operator[](Int k) const{
    return bool((bit[k>>5]>>(k&31))&1);
  }
  
  Int rank(Int k){
    return sum[k>>5]+__builtin_popcount(bit[k>>5]&((1<<(k&31))-1));
  }
  
  Int rank(bool v,Int k){
    return (v?rank(k):k-rank(k));
  }

  Int select(bool v,Int k){
    if(k<0||rank(v,len)<=k) return -1;
    Int low=0,high=len;
    while(low+1<high){
      Int mid=(low+high)>>1;
      if(rank(v,mid)>=k+1) high=mid;
      else low=mid;
    }
    return high-1;
  }

  Int select(bool v,Int i,Int l){
    return select(v,i+rank(v,l));
  }
};

template<class T,Int MAXLOG>
struct WaveletMatrix{
  Int len;
  FullyIndexableDictionary mat[MAXLOG];
  Int zs[MAXLOG],buff1[MAXLOG],buff2[MAXLOG];
  static const T npos=-1;
  
  Int freq_dfs(Int d,Int l,Int r,T val,T a,T b){
    if(l==r) return 0;
    if(d==MAXLOG) return (a<=val&&val<b)?r-l:0;
    T nv=1ULL<<(MAXLOG-d-1)|val;
    T nnv=((1ULL<<(MAXLOG-d-1))-1)|nv;
    if(nnv<a||b<=val) return 0;
    if(a<=val&&nnv<b) return r-l;
    Int lc=mat[d].rank(1,l),rc=mat[d].rank(1,r);
    return freq_dfs(d+1,l-lc,r-rc,val,a,b)
      +freq_dfs(d+1,lc+zs[d],rc+zs[d],nv,a,b);
  }
  
  WaveletMatrix(vector<T> data){
    len=data.size();
    vector<T> l(len),r(len);
    for(Int dep=0;dep<MAXLOG;dep++){
      mat[dep]=FullyIndexableDictionary(len+1);
      Int p=0,q=0;
      for(Int i=0;i<len;i++){
	bool k=(data[i]>>(MAXLOG-(dep+1)))&1;
	if(k) r[q++]=data[i],mat[dep].set(i);
	else  l[p++]=data[i];
      }
      zs[dep]=p;
      mat[dep].build();
      swap(l,data);
      for(Int i=0;i<q;i++) data[p+i]=r[i];
    }
  }
  
  T access(Int k){
    T res=0;
    bool bit;
    for(Int dep=0;dep<MAXLOG;dep++){
      bit=mat[dep][k];
      res=(res<<1)|bit;
      k=mat[dep].rank(bit,k)+zs[dep]*dep;
    }
    return res;
  }

  // return the number of v in [0,k)
  Int rank(T v,Int k){
    Int l=0,r=k;
    for(Int dep=0;dep<MAXLOG;dep++){
      buff1[dep]=l;buff2[dep]=r;
      bool bit=(v>>(MAXLOG-(dep+1)))&1;
      l=mat[dep].rank(bit,l)+zs[dep]*bit;
      r=mat[dep].rank(bit,r)+zs[dep]*bit;
    }
    return r-l;
  }

  // return the position of k-th v
  Int select(T v,Int k){
    rank(v,len);
    for(Int dep=MAXLOG-1;dep>=0;dep--){
      bool bit=(v>>(MAXLOG-(dep+1)))&1;
      k=mat[dep].select(bit,k,buff1[dep]);
      if(k>=buff2[dep]||k<0) return -1;
      k-=buff1[dep];
    }
    return k;
  }

  Int select(T v,Int k,Int l){
    return select(v,k+rank(v,l));
  }

  // return k-th largest value in [l,r)
  T quantile(Int l,Int r,Int k){
    if(r-l<=k||k<0) return -1;
    T res=0;
    for(Int dep=0;dep<MAXLOG;dep++){
      Int p=mat[dep].rank(1,l);
      Int q=mat[dep].rank(1,r);
      if(q-p>k){
	l=p+zs[dep];
	r=q+zs[dep];
	res|=(1<<(MAXLOG-(dep+1)));
      }else{
	k-=(q-p);
	l-=p;
	r-=q;
      }
    }
    return res;
  }
  
  T rquantile(Int l,Int r,Int k){
    return quantile(l,r,r-l-k-1);
  }
  
  // return number of points in [left, right) * [lower, upper)
  Int rangefreq(Int left,Int right,T lower,T upper){
    return freq_dfs(0,left,right,0,lower,upper);
  }

  pair<Int, Int> ll(Int l,Int r,T v){
    Int res=0;
    for(Int dep=0;dep<MAXLOG;dep++){
      buff1[dep]=l;buff2[dep]=r;
      bool bit=(v>>(MAXLOG-(dep+1)))&1;
      if(bit) res+=r-l+mat[dep].rank(bit,l)-mat[dep].rank(bit,r);
      l=mat[dep].rank(bit,l)+zs[dep]*bit;
      r=mat[dep].rank(bit,r)+zs[dep]*bit;
    }
    return make_pair(res,r-l);    
  }
  
  Int lt(Int l,Int r,T v){
    auto p=ll(l,r,v);
    return p.first;
  }
  
  Int le(Int l,Int r,T v){
    auto p=ll(l,r,v);
    return p.first+p.second;
  }
  
  T succ(Int l,Int r,T v){
    Int k=le(l,r,v);
    return k==r-l?npos:rquantile(l,r,k);
  }

  T pred(Int l,Int r,T v){
    Int k=lt(l,r,v);
    return k?rquantile(l,r,k-1):npos;
  }
};



template<typename T> 
struct BIT{
  Int n;
  vector<T> bit;
  //1-indexed
  BIT():n(-1){}
  BIT(Int n_,T d):n(n_),bit(n_+1,d){}
  
  T sum(Int i){
    T s=bit[0];
    for(Int x=i;x>0;x-=(x&-x))
      s+=bit[x];
    return s;
  }
  void add(Int i,T a){
    if(i==0) return;
    for(Int x=i;x<=n;x+=(x&-x))
      bit[x]+=a;
  }
  
  Int lower_bound(Int w){
    if(w<=0) return 0;
    Int x=0,r=1;
    while(r<n) r<<=1;
    for(Int k=r;k>0;k>>=1){
      if(x+k<=n&&bit[x+k]<w){
	w-=bit[x+k];
	x+=k;
      }
    }
    return x+1;
  }
  
  T sum0(Int i){
    return sum(i+1);
  }
  void add0(Int i,T a){
    add(i+1,a);
  }

  T query(Int l,Int r){
    return sum(r-1)-sum(l-1);
  }

  T query0(Int l,Int r){
    return sum(r)-sum(l);
  }
};


template<typename T>
vector<T> compress(vector<T> v){
  sort(v.begin(),v.end());
  v.erase(unique(v.begin(),v.end()),v.end());
  return v;
}

template<typename T>
map<T, Int> dict(const vector<T> &v){
  map<T, Int> res;
  for(Int i=0;i<(Int)v.size();i++)
    res[v[i]]=i;
  return res;
}


template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}

//INSERT ABOVE HERE
signed main(){
  Int n,k;
  cin>>n>>k;
  vector<Int> a(n);
  for(Int i=0;i<n;i++) cin>>a[i];
  WaveletMatrix<Int,32> wm(a);

  auto vx=compress(a);
  auto mx=dict(vx);
  
  BIT<Int> bit1(n+10,0),bit2(n+10,0);

  Int ans=1e18,sum=0;
  for(Int i=0;i<k;i++){
    bit1.add0(mx[a[i]],1);
    bit2.add0(mx[a[i]],a[i]);
    sum+=a[i];
  }
  
  for(Int i=0;i+k<=n;i++){
    Int j=i+k;
    Int x=wm.quantile(i,j,k>>1);

    Int p=bit1.sum0(mx[x]),q=k-p;
    Int s=bit2.sum0(mx[x]);
    chmin(ans,p*x-s+(sum-s)-q*x);
    
    bit1.add0(mx[a[i]],-1);
    bit2.add0(mx[a[i]],-a[i]);
    sum-=a[i];
    
    if(j==n) continue;    
    bit1.add0(mx[a[j]],1);
    bit2.add0(mx[a[j]],a[j]);
    sum+=a[j];
  }
  cout<<ans<<endl;
  return 0;
}