import java.io.*;
import java.util.*;

public class Main {
  private static int solve(int n, int k, int[] xs) {
    if (xs[0] >= 0) {
      return xs[k - 1];
    }
    if (xs[n - 1] <= 0) {
      return -1 * xs[n - k];
    }
    
    int index = 0;
    while (xs[index] < 0) {
      index++;
    }
    
    int[] positiveDistances = new int[n - index + 1];
    positiveDistances[0] = 0;
    for (int i = index; i < n; i++) {
      positiveDistances[i - index + 1] = xs[i];
    }
    
    int[] negativeDistances = new int[index + 1];
    negativeDistances[0] = 0;
    for (int i = index - 1; i >= 0; i--) {
      negativeDistances[index - i] = -1 * xs[i];
    }
    
    int answer = Integer.MAX_VALUE;
    for (int j = 0; j <= k; j++) {
      if (j < positiveDistances.length && k - j < negativeDistances.length) {
        answer = Math.min(answer, positiveDistances[j] * 2 + negativeDistances[k - j] * 1);
        answer = Math.min(answer, positiveDistances[j] * 1 + negativeDistances[k - j] * 2);
      }
    }
    return answer;
  }
  
  private static void execute(ContestReader reader, PrintWriter out) {
    int n = reader.nextInt();
    int k = reader.nextInt();
    int[] xs = reader.nextInt(n);
    out.println(solve(n, k, xs));
  }
  
  public static void main(String[] args) {
    ContestReader reader = new ContestReader(System.in);
    PrintWriter out = new PrintWriter(System.out);
    execute(reader, out);
    out.flush();
  }
}

class ContestReader {
  private BufferedReader reader;
  private StringTokenizer tokenizer;
  
  ContestReader(InputStream in) {
    reader = new BufferedReader(new InputStreamReader(in));
  }
  
  public String next() {
    while (tokenizer == null || !tokenizer.hasMoreTokens()) {
      try {
        tokenizer = new java.util.StringTokenizer(reader.readLine());
      } catch (Exception e) {
        throw new RuntimeException(e);
      }
    }
    return tokenizer.nextToken();
  }
  
  public int nextInt() {
    return Integer.parseInt(next());
  }
  
  public long nextLong() {
    return Long.parseLong(next());
  }
  
  public double nextDouble() {
    return Double.parseDouble(next());
  }
  
  public String[] next(int n) {
    String[] array = new String[n];
    for (int i = 0; i < n; i++) {
      array[i] = next();
    }
    return array;
  }
  
  public int[] nextInt(int n) {
    int[] array = new int[n];
    for (int i = 0; i < n; i++) {
      array[i] = nextInt();
    }
    return array;
  }
  
  public long[] nextLong(int n) {
    long[] array = new long[n];
    for (int i = 0; i < n; i++) {
      array[i] = nextLong();
    }
    return array;
  }
  
  public double[] nextDouble(int n) {
    double[] array = new double[n];
    for (int i = 0; i < n; i++) {
      array[i] = nextDouble();
    }
    return array;
  }
  
  public char[] nextCharArray() {
    return next().toCharArray();
  }
  
  public int[][] nextInt(int n, int m) {
    int[][] matrix = new int[n][m];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        matrix[i][j] = nextInt();
      }
    }
    return matrix;
  }
  
  public long[][] nextLong(int n, int m) {
    long[][] matrix = new long[n][m];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        matrix[i][j] = nextLong();
      }
    }
    return matrix;
  }
  
  public double[][] nextDouble(int n, int m) {
    double[][] matrix = new double[n][m];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        matrix[i][j] = nextDouble();
      }
    }
    return matrix;
  }
  
  public char[][] nextCharArray(int n) {
    char[][] matrix = new char[n][];
    for (int i = 0; i < n; i++) {
      matrix[i] = next().toCharArray();
    }
    return matrix;
  }
}


Measured memory_bytes: 35864