// includes
#include "bits/stdc++.h"
using namespace std;
// macros
#define ll long long
#define MOD  998244353 //1000000007 // 100000000  //
#define pii pair<ll, ll>
#define piii pair<ll, pii>
#define sz(x) ((ll)(x).size())
#define ft first
#define sd second
#define pb push_back
#define rep(i, n) for(ll i = 0; i < n; i++)
#define repr(i, n) for(ll i = n-1; i >= 0; i--)
#define itr(it, x) for(auto it = x.begin(); it != x.end(); it++)
#define mem(a, b) memset(a, (ll)b, sizeof(a))
#define all(v) v.begin(), v.end()
#define allr(v) v.rbegin(), v.rend()
#define edge(v, x, y) v[x].pb(y); v[y].pb(x);
#define popc __builtin_popcount
#define ANS(s) {cout << s << "\n"; return;}
// functions
template <typename T> void unique(T& c){c.erase(std::unique(c.begin(), c.end()), c.end());}
template <class T>bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;}
template <class T>bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;}
template <typename T> istream &operator>>(istream &is, vector<T> &vec){for(auto &v: vec)is >> v; return is;}
template <typename T> ostream &operator<<(ostream &os, const vector<T>& vec){for(int i = 0; i < vec.size(); i++){ os << vec[i]; if(i + 1 != vec.size())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p){os << "(" << p.first << ", " << p.second << ")"; return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << "(" << itr->first << ", " << itr->second << ")"; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const unordered_map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << "(" << itr->first << ", " << itr->second << ")"; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
// constants
const ll N = 1e5+5, M = 1e6+5, A = 1e7+5, inf = 1e9;
const long long linf = 1LL << 60;
const double er = 1e-10, pi = 3.141592653589793238463;
const ll lx[4] = {0, 1, -1, 0};
const ll ly[4] = {1, 0, 0, -1};
const ll dx[8] = {0, 0, 1, -1, 1, -1, 1, -1};
const ll dy[8] = {1, -1, 0, 0, 1, 1, -1, -1};
// io
struct fast_io{
  fast_io(){ios_base::sync_with_stdio(false); cin.tie(0); cout << fixed << setprecision(20);}
} fast_io_;


void solve()
{
    ll n, m;
    cin >> n >> m;
    vector<ll> a(n); cin >> a;
    ll ans = inf;
    ll l = 0, r = m-1;
    rep(i, n)
    {
        if(a[r] <= 0){
            ans  = min(ans, abs(a[l]));
        }
        else if(a[l] >= 0){
            ans = min(ans, a[r]);
        }
        else{
            ans = min({ans, abs(a[l])*2 + a[r], abs(a[l]) + a[r]*2 });
        }//cout << ans << " ";
        l++, r++;
        if(r == n) break;
    }
    cout << ans;
}

int main(int argc, char const* argv[])
{
    ll t = 1; //cin >> t;
    while(t--) {
        solve();
    }
    return 0;
}

#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
#include<cmath>
#include<bitset>
#include<deque>
#include<functional>
#include<iterator>
#include<map>
#include<set>
#include<stack>
#include<queue>
#include<utility>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> P;
#define a first
#define b second
#define sz(x) (ll)((x).size())
#define pb push_back
#define mp make_pair
#define bg begin()
#define ed end()
#define all(x) (x).bg,(x).ed
#define rep(i,n) for(ll i=0;i<(n);i++)
#define rep1(i,n) for(ll i=1;i<=(n);i++)
#define rrep(i,n) for(ll i=(n)-1;i>=0;i--)
#define rrep1(i,n) for(ll i=(n);i>=1;i--)
#define FOR(i,a,b) for(ll i=(a);i<(b);i++)
const ll MOD=1000000007;
const ll INF=1000000000000000;
template<class T> inline bool chmin(T& a, T b){if(a>b){a=b;return true;}return false;}
template<class T> inline bool chmax(T& a, T b){if(a<b){a=b;return true;}return false;}
ll maxx(ll x,ll y,ll z){return max(max(x,y),z);}
ll minn(ll x,ll y,ll z){return min(min(x,y),z);}
ll gcd(ll x,ll y){if(x%y==0) return y;else return gcd(y,x%y);}
ll lcm(ll x,ll y){return x*(y/gcd(x,y));}
ll digsz(ll x){if(x==0) return 1;else{ll ans=0;while(x){x/=10;ans++;}return ans;}}
ll digsum(ll x){ll sum=0;while(x){sum+=x%10;x/=10;}return sum;}
vector<ll> pw2(62,1);vector<ll> pw10(19,1);
ll dx[8]={0,0,-1,1,-1,1,-1,1};
ll dy[8]={1,-1,0,0,1,1,-1,-1};
vector<vector<ll> > c(10,vector<ll>(10,0));

int main(){
    {rep1(i,61) pw2[i]=2*pw2[i-1];}
    {rep1(i,18) pw10[i]=10*pw10[i-1];}
    
    ll N,K; cin>>N>>K;
    vector<ll> minus;
    vector<ll> plus;
    vector<ll> zero;
    rep(i,N){
        ll x; cin>>x;
        if(x<0) minus.pb(x);
        else if(x==0) zero.pb(x);
        else plus.pb(x);
    }
    ll m=sz(minus),p=sz(plus),need=K-sz(zero);
    minus.pb(0);
    plus.pb(0);
    sort(all(minus),greater<ll>());
    sort(all(plus));
    
    ll ans=INF;
    rep(i,min(need,m)+1){
        if(need-i > p) continue;
        ll X=-minus[i];
        ll Y=plus[need-i];
        
        chmin(ans,max(X,Y)+min(X,Y)*2);
    }
    cout<<ans<<endl;
}
