You are given a chessboard of size 1 × n. It is guaranteed that n is even. The chessboard is painted like this: "BWBW...BW".

Some cells of the board are occupied by the chess pieces. Each cell contains no more than one chess piece. It is known that the total number of pieces equals to <image>.

In one step you can move one of the pieces one cell to the left or to the right. You cannot move pieces beyond the borders of the board. You also cannot move pieces to the cells that are already occupied.

Your task is to place all the pieces in the cells of the same color using the minimum number of moves (all the pieces must occupy only the black cells or only the white cells after all the moves are made).

Input

The first line of the input contains one integer n (2 ≤ n ≤ 100, n is even) — the size of the chessboard. 

The second line of the input contains <image> integer numbers <image> (1 ≤ pi ≤ n) — initial positions of the pieces. It is guaranteed that all the positions are distinct.

Output

Print one integer — the minimum number of moves you have to make to place all the pieces in the cells of the same color.

Examples

Input

6
1 2 6


Output

2


Input

10
1 2 3 4 5


Output

10

Note

In the first example the only possible strategy is to move the piece at the position 6 to the position 5 and move the piece at the position 2 to the position 3. Notice that if you decide to place the pieces in the white cells the minimum number of moves will be 3.

In the second example the possible strategy is to move <image> in 4 moves, then <image> in 3 moves, <image> in 2 moves and <image> in 1 move.
import java.io.*;
import java.math.BigInteger;
import java.util.*;

@SuppressWarnings("unused")
public class Practice
{
	public static class Row
	{
		int		index	= 0;
		int		width	= 0;
		boolean	filled	= false;

	}

	private static InputStream		stream;
	private static byte[]			buf	= new byte[1024];
	private static int				curChar;
	private static int				numChars;
	private static SpaceCharFilter	filter;
	private static PrintWriter		pw;
	private static long				mod	= 1000000000 + 7;

	private static void soln()
	{
		int N = nextInt();
		int pos[] = new int[N / 2 + 1];

		pos[0] = 0;
		for (int i = 1; i <= N / 2; i++)
			pos[i] = nextInt();

		Arrays.sort(pos);

		int wCount = 0, bCount = 0;

		for (int i = 1, temp; i <= N / 2; i++)
		{
			temp = pos[i] - 2 * i;
			wCount += mod(temp);
			bCount += mod(temp + 1);
		}

		pw.println(min(wCount, bCount));

	}

	public static int mod(int n)
	{
		if (n < 0)
			return -n;

		return n;
	}

	public static int min(int a, int b)
	{
		if (a < b)
			return a;
		return b;
	}

	public static class Segment
	{
		private int[]		tree;
		private boolean[]	lazy;
		private int			size;
		private int			n;

		private class node
		{
			private int	a;
			private int	b;
			private int	c;

			public node(int x, int y, int z)
			{
				a = x;
				b = y;
				c = z;
			}
		}

		public Segment(int n)
		{
			// this.base=arr;
			int x = (int) (Math.ceil(Math.log(n) / Math.log(2)));
			size = 2 * (int) Math.pow(2, x) - 1;
			tree = new int[size];
			lazy = new boolean[size];
			this.n = n;
			build(0, 0, n - 1);
		}

		public void build(int id, int l, int r)
		{
			if (l == r)
			{
				return;
			}
			int mid = (l + r) / 2;
			build(2 * id + 1, l, mid);
			build(2 * id + 2, mid + 1, r);
			tree[id] = tree[2 * id + 1] + tree[2 * id + 2];
		}

		public int query(int l, int r)
		{
			return queryUtil(l, r, 0, 0, n - 1);
		}

		private int queryUtil(int x, int y, int id, int l, int r)
		{
			if (l > y || x > r)
				return 0;
			if (x <= l && r <= y)
			{
				// if(!lazy[id])
				return tree[id];
				// else
				// return tree[id][0];
			}
			int mid = l + (r - l) / 2;
			shift(id);
			return queryUtil(x, y, 2 * id + 1, l, mid) + queryUtil(x, y, 2 * id + 2, mid + 1, r);
		}

		public void update(int x, int y, int colour, int id, int l, int r)
		{
			// System.out.println(l+" "+r+" "+x);
			if (x > r || y < l)
				return;
			if (x <= l && r <= y)
			{

				return;
			}
			int mid = l + (r - l) / 2;
			shift(id);
			update(x, y, colour, 2 * id + 1, l, mid);
			update(x, y, colour, 2 * id + 2, mid + 1, r);
			tree[id] = tree[2 * id + 1] + tree[2 * id + 2];
		}

		public void shift(int id)
		{

		}

	}

	public static void fft(double[] a, double[] b, boolean invert)
	{
		int count = a.length;
		for (int i = 1, j = 0; i < count; i++)
		{
			int bit = count >> 1;
			for (; j >= bit; bit >>= 1)
				j -= bit;
			j += bit;
			if (i < j)
			{
				double temp = a[i];
				a[i] = a[j];
				a[j] = temp;
				temp = b[i];
				b[i] = b[j];
				b[j] = temp;
			}
		}
		for (int len = 2; len <= count; len <<= 1)
		{
			int halfLen = len >> 1;
			double angle = 2 * Math.PI / len;
			if (invert)
				angle = -angle;
			double wLenA = Math.cos(angle), wLenB = Math.sin(angle);
			for (int i = 0; i < count; i += len)
			{
				double wA = 1, wB = 0;
				for (int j = 0; j < halfLen; j++)
				{
					double uA = a[i + j], uB = b[i + j];
					double vA = a[i + j + halfLen] * wA - b[i + j + halfLen] * wB;
					double vB = a[i + j + halfLen] * wB + b[i + j + halfLen] * wA;
					a[i + j] = uA + vA;
					b[i + j] = uB + vB;
					a[i + j + halfLen] = uA - vA;
					b[i + j + halfLen] = uB - vB;
					double nextWA = wA * wLenA - wB * wLenB;
					wB = wA * wLenB + wB * wLenA;
					wA = nextWA;
				}
			}
		}
		if (invert)
		{
			for (int i = 0; i < count; i++)
			{
				a[i] /= count;
				b[i] /= count;
			}
		}
	}

	static void multiply(long[][] a, long[][] b, long m)
	{
		int n = a.length;
		long[][] mul = new long[n][n];
		for (int i = 0; i < n; i++)
		{
			for (int j = 0; j < n; j++)
			{
				mul[i][j] = 0;
				for (int k = 0; k < n; k++)
					mul[i][j] = (mul[i][j] + (a[i][k] * b[k][j]) % m) % m;
			}
		}
		for (int i = 0; i < n; i++)
			for (int j = 0; j < n; j++)
				a[i][j] = mul[i][j];
	}

	private static long pow(long a, long b, long c)
	{
		if (b == 0)
			return 1;
		long p = pow(a, b / 2, c);
		p = (p * p) % c;
		return (b % 2 == 0) ? p : (a * p) % c;
	}

	private static long gcd(long n, long l)
	{
		if (l == 0)
			return n;
		return gcd(l, n % l);
	}

	public static void main(String[] args) throws Exception
	{
		// new Thread(null, new Runnable()
		// {
		// @Override
		// public void run()
		// {
		// /*try {
		// InputReader(new
		// FileInputStream("C:\\Users\\hardik\\Desktop\\B-large-practice.in"));
		// } catch (FileNotFoundException e) { // TODO Auto-generated catch
		// block
		// e.printStackTrace();
		// } */
		// InputReader(System.in);
		// pw = new PrintWriter(System.out);
		// /*try {
		// pw=new PrintWriter(new
		// FileOutputStream("C:\\Users\\hardik\\Desktop\\out.txt"));
		// } catch (FileNotFoundException e) { // TODO Auto-generated catch
		// block
		// e.printStackTrace();
		// }*/
		// soln();
		// pw.close();
		// }
		// }, "1", 1 << 26).start();

		/*
		 * try {
		 * InputReader(new
		 * FileInputStream("C:\\Users\\hardik\\Desktop\\B-large-practice.in"));
		 * } catch (FileNotFoundException e) { // TODO Auto-generated catch
		 * block
		 * e.printStackTrace();
		 * }
		 */
		InputReader(System.in);
		pw = new PrintWriter(System.out);
		/*
		 * try {
		 * pw=new PrintWriter(new
		 * FileOutputStream("C:\\Users\\hardik\\Desktop\\out.txt"));
		 * } catch (FileNotFoundException e) { // TODO Auto-generated catch
		 * block
		 * e.printStackTrace();
		 * }
		 */
		soln();
		pw.close();
	}

	public static void InputReader(InputStream stream1)
	{
		stream = stream1;
	}

	private static boolean isWhitespace(int c)
	{
		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	}

	private static boolean isEndOfLine(int c)
	{
		return c == '\n' || c == '\r' || c == -1;
	}

	private static int read()
	{
		if (numChars == -1)
			throw new InputMismatchException();
		if (curChar >= numChars)
		{
			curChar = 0;
			try
			{
				numChars = stream.read(buf);
			}
			catch (IOException e)
			{
				throw new InputMismatchException();
			}
			if (numChars <= 0)
				return -1;
		}
		return buf[curChar++];
	}

	private static int nextInt()
	{
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-')
		{
			sgn = -1;
			c = read();
		}
		int res = 0;
		do
		{
			if (c < '0' || c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		}
		while (!isSpaceChar(c));
		return res * sgn;
	}

	private static long nextLong()
	{
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-')
		{
			sgn = -1;
			c = read();
		}
		long res = 0;
		do
		{
			if (c < '0' || c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		}
		while (!isSpaceChar(c));
		return res * sgn;
	}

	private static String nextToken()
	{
		int c = read();
		while (isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do
		{
			res.appendCodePoint(c);
			c = read();
		}
		while (!isSpaceChar(c));
		return res.toString();
	}

	private static String nextLine()
	{
		int c = read();
		while (isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do
		{
			res.appendCodePoint(c);
			c = read();
		}
		while (!isEndOfLine(c));
		return res.toString();
	}

	private static int[] nextIntArray(int n)
	{
		int[] arr = new int[n];
		for (int i = 0; i < n; i++)
		{
			arr[i] = nextInt();
		}
		return arr;
	}

	private static long[] nextLongArray(int n)
	{
		long[] arr = new long[n];
		for (int i = 0; i < n; i++)
		{
			arr[i] = nextLong();
		}
		return arr;
	}

	private static void pArray(int[] arr)
	{
		for (int i = 0; i < arr.length; i++)
		{
			System.out.print(arr[i] + " ");
		}
		System.out.println();
		return;
	}

	private static void pArray(long[] arr)
	{
		for (int i = 0; i < arr.length; i++)
		{
			System.out.print(arr[i] + " ");
		}
		System.out.println();
		return;
	}

	private static boolean isSpaceChar(int c)
	{
		if (filter != null)
			return filter.isSpaceChar(c);
		return isWhitespace(c);
	}

	private static char nextChar()
	{
		int c = read();
		while (isSpaceChar(c))
			c = read();
		char c1 = (char) c;
		while (!isSpaceChar(c))
			c = read();
		return c1;
	}

	private interface SpaceCharFilter
	{
		public boolean isSpaceChar(int ch);
	}
}