#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vint;
typedef vector<double> vd;
typedef vector<ll> vll;
typedef vector<string> vstr;
typedef vector<vector<int>> vvint;
typedef vector<pair<int, int>> vpii;
typedef vector<pair<ll, ll>> vpll;
typedef priority_queue<int, vector<int>, greater<int>> spqint; //小さい順に取り出し
typedef priority_queue<ll, vector<ll>, greater<ll>> spqll;     //小さい順に取り出し
typedef priority_queue<int, vector<int>, less<int>> bpqint;    //大きい順に取り出し
typedef priority_queue<ll, vector<ll>, less<ll>> bpqll;        //大きい順に取り出し

#define REP(i, n) for (ll i = 0; i < (ll)(n); i++)
#define FOR(i, a, b) for (ll i = (ll)a; i < (ll)b; i++)
#define IREP(i, v) for (auto i = (v).begin(); i != (v).end(); i++)
#define FI first
#define SE second
#define MP make_pair
#define MT make_tuple
#define PB push_back
#define PF push_front
#define TS to_string
#define BS binary_search
#define LB lower_bound
#define UB upper_bound
#define NP next_permutation
#define ALL(v) (v).begin(), (v).end()
#define SZ(x) (ll) x.size()
#define SP(x) setprecision((ll)x)


int INF = 1e9;
int NIL = -1;
ll MOD = 1000000007;
ll LINF = 1e18;
double EPS = 1e-9;
double PI = M_PI;
int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; } //最大公約数
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }     //最小公倍数

void yes(){ cout << "Yes" << endl;}
void no(){ cout << "No" << endl;}
//-----------------------------------------

//-----------------------------------------
int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    std::chrono::system_clock::time_point start,end;
    start = std::chrono::system_clock::now();

    ll n, k ;
    cin >> n >> k ;
    vll pa ;
    vll ma ;
    pa.PB(0) ;
    ma.PB(0) ;
    REP(i,n){
        ll a ;
        cin >> a ;
        if(a==0){
            k-- ;
        }
        else if(a>0){
            pa.PB(a) ;
        }
        else{
            ma.PB(-a) ;
        }
    }
    sort(ALL(ma)) ;
    sort(ALL(pa)) ;
    ll sp = SZ(pa) ;
    ll sm = SZ(ma) ;

    ll ans = LINF ;

    for(ll i=0;i<=k;i++){
        ll tmp ;
        if(k-i<sm && i<sp){
            tmp = 2*min(pa[i],ma[k-i]) + max(pa[i],ma[k-i]) ;
            ans = min(ans,tmp) ;
        }
    }

    cout << ans <<endl;







    end = std::chrono::system_clock::now();
    auto elapsed = std::chrono::duration_cast< std::chrono::milliseconds >(end - start).count();
    //std::cout << elapsed <<"ms"<< std::endl;

    

    return 0;
}


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

const int64_t MOD = 1000000007;
typedef int64_t ll;
typedef uint64_t ull;

#define FOR(i, start, end) for(uint64_t i=start; i<end; i++)
#define REP(i, n) FOR(i, 0, n)

// 最大公約数gcd
// 最小公倍数lcm=m*n/gcd
uint64_t gcd(uint64_t m, uint64_t n) {
  uint64_t temp;
  while (m % n != 0){
    temp = n;
    n = m % n;
    m = temp;
  }
  return n;
}

uint64_t lcm(uint64_t m, uint64_t n) {
  return (m*n)/gcd(m,n);
}

// vector<vector<uint64_t> > v(n+1, vector<uint64_t>(n+1, 0))
// v[n][k]に組み合わせ数が入る。
void comb(vector<vector <uint64_t> > &v){
  for(uint64_t i = 0;i <v.size(); i++){
    v[i][0]=1;
    v[i][i]=1;
  }
  for(uint64_t k = 1;k <v.size();k++){
    for(uint64_t j = 1;j<k;j++){
      v[k][j]=(v[k-1][j-1]+v[k-1][j]);
    }
  }
}

// 掛け算オーバーフロー判定
bool is_product_overflow(uint64_t a, uint64_t b) {

	uint64_t prod = a * b;
	
	return (prod / b != a);
}

//素因数分解
void primeFactorization(uint64_t a, list<uint64_t> &factors){ //素因数分解を出力するプログラム
  long i,sq;
  if(a%2==0){ //偶数の場合
    factors.push_back(2);
    primeFactorization(a/2,factors); //2で割った値で再帰
    return;
  }
  sq = sqrt(a);
  for(i=3;i<=sq;i+=2){ //3以上√a以下の奇数の場合
	if(a%i==0){
	  factors.push_back(i);
      primeFactorization(a/i,factors); //割れた値で再帰
      return;
	}
  }
  //偶数でも3以上√a以下の奇数の場合でも割り切れない場合
  if(a!=1){ //aが1でないなら、a自身は素数
    factors.push_back(a);
  }
}

// フェルマーの小定理
// mod. m での a の逆元 a^{-1} を計算する
// (a/b)%m = a*movinv(b,m)%m  
int64_t modinv(int64_t a, int64_t m) {
    int64_t b = m, u = 1, v = 0;
    while (b) {
        int64_t t = a / b;
        a -= t * b; swap(a, b);
        u -= t * v; swap(u, v);
    }
    u %= m;
    if (u < 0) u += m;
    return u;
}

// 円周率
// M_PI

// #include <iomanip> // setprecisionを使用するのに必要
// cout << std::fixed << std::setprecision(15) << y << endl;

// 昇順
// priority_queue<int, vector<int>, greater<int> > queue;

ll pCount(int x){
  if(x==0) return 1;
  return pCount(x-1)*2 + 1;
}

ll allCount(int x){
  if(x==0) return 1;
  return allCount(x-1)*2 + 3;
}


signed main() {
  int n,k;
  cin >> n >> k;
  k--;
  vector<int> pos(n);
  for(int i=0;i<n;i++){
    cin >> pos[i];
  }
  
  int minDist = 1000000000;
  for(int i=0;i<n-k;i++){
    if((pos[i]<=0 && pos[i+k]<=0)
      ||(pos[i]>=0 && pos[i+k]>=0)){
      minDist = min(minDist, (abs(pos[i])>abs(pos[i+k]))?abs(pos[i]):abs(pos[i+k]));
    }
    else if(pos[i]<=0 && pos[i+k]>=0){
      if(abs(pos[i]) < pos[i+k]){
        minDist = min(minDist, abs(pos[i])*2+pos[i+k]);
      }
      else{
        minDist = min(minDist, pos[i+k]*2+abs(pos[i]));
      }
    }
  }
  
  cout << minDist << endl;
  
  
  return 0;
}

