import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
public class Solution 
{
    static class Reader
    {
        final private int BUFFER_SIZE = 1 << 16;
        private DataInputStream din;
        private byte[] buffer;
        private int bufferPointer, bytesRead;
 
        public Reader()
        {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }
 
        public Reader(String file_name) throws IOException
        {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }
 
        public String readLine() throws IOException
        {
            byte[] buf = new byte[64]; // line length
            int cnt = 0, c;
            while ((c = read()) != -1)
            {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        }
 
        public int nextInt() throws IOException
        {
            int ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do
            {
                ret = ret * 10 + c - '0';
            }  while ((c = read()) >= '0' && c <= '9');
 
            if (neg)
                return -ret;
            return ret;
        }
 
        public long nextLong() throws IOException
        {
            long ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');
            if (neg)
                return -ret;
            return ret;
        }
 
        public double nextDouble() throws IOException
        {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
 
            do {
                ret = ret * 10 + c - '0';
            }
            while ((c = read()) >= '0' && c <= '9');
 
            if (c == '.')
            {
                while ((c = read()) >= '0' && c <= '9')
                {
                    ret += (c - '0') / (div *= 10);
                }
            }
 
            if (neg)
                return -ret;
            return ret;
        }
 
        private void fillBuffer() throws IOException
        {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
            if (bytesRead == -1)
                buffer[0] = -1;
        }
 
        private byte read() throws IOException
        {
            if (bufferPointer == bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        }
 
        public void close() throws IOException
        {
            if (din == null)
                return;
            din.close();
        }
    }
    
    @SuppressWarnings("unchecked")
     public static void main(String[] args) throws Exception
     {
         Reader r=new Reader();
         int n=r.nextInt();
         int[] ar=new int[n/2];
         boolean[] ovis=new boolean[n+1];
         boolean[] evis=new boolean[n+1];
         //int emin=Integer.MAX_VALUE,omin=Integer.MAX_VALUE;
         for(int i=0;i<n/2;i++)
         {
             ar[i]=r.nextInt();
             ovis[ar[i]]=true;
             evis[ar[i]]=true;
         }
         Arrays.sort(ar);
         int even=0,odd=0;
         
         for(int i=0;i<n/2;i++)
         {
             if(ar[i]%2==0)
             {
                //find the closest unoccupied odd
                 //all at odd positions
                 int left=ar[i]-1;
                 int right=ar[i]+1;
                 int ans1=Integer.MAX_VALUE,ans2=Integer.MAX_VALUE;
                 while(left>0)
                 {
                     if(ovis[left]==false)
                     {
                         ans1=ar[i]-left;
                         ovis[left]=true;
                         break;
                     }
                     left-=2;
                 }
                 while(right<=n)
                 {
                     if(ovis[right]==false)
                     {
                         ans2=right-ar[i];
                         ovis[right]=true;
                         break;
                     }
                     right+=2;
                 }
                 odd+=(int)Math.min(ans1,ans2);
             }
             else
             {
                 //all even
                 int left=ar[i]-1;
                 int right=ar[i]+1;
                 int ans1=Integer.MAX_VALUE,ans2=Integer.MAX_VALUE;
                 while(left>0)
                 {
                     if(evis[left]==false)
                     {
                         ans1=ar[i]-left;
                         evis[left]=true;
                         break;
                     }
                     left-=2;
                 }
                 while(right<=n)
                 {
                     if(evis[right]==false)
                     {
                         ans2=right-ar[i];
                         evis[right]=true;
                         break;
                     }
                     right+=2;
                 }
                 even+=(int)Math.min(ans1,ans2);
             }
         }
         //System.out.println(even+" "+odd);
         int answer=(int)Math.min(odd,even);
         if(answer<0)
         {
             System.out.println("0");
         }
         else
         {
             System.out.println(answer);
         }
     }
}   