Sereja owns a restaurant for n people. The restaurant hall has a coat rack with n hooks. Each restaurant visitor can use a hook to hang his clothes on it. Using the i-th hook costs ai rubles. Only one person can hang clothes on one hook.

Tonight Sereja expects m guests in the restaurant. Naturally, each guest wants to hang his clothes on an available hook with minimum price (if there are multiple such hooks, he chooses any of them). However if the moment a guest arrives the rack has no available hooks, Sereja must pay a d ruble fine to the guest. 

Help Sereja find out the profit in rubles (possibly negative) that he will get tonight. You can assume that before the guests arrive, all hooks on the rack are available, all guests come at different time, nobody besides the m guests is visiting Sereja's restaurant tonight.

Input

The first line contains two integers n and d (1 ≤ n, d ≤ 100). The next line contains integers a1, a2, ..., an (1 ≤ ai ≤ 100). The third line contains integer m (1 ≤ m ≤ 100).

Output

In a single line print a single integer — the answer to the problem.

Examples

Input

2 1
2 1
2


Output

3


Input

2 1
2 1
10


Output

-5

Note

In the first test both hooks will be used, so Sereja gets 1 + 2 = 3 rubles.

In the second test both hooks will be used but Sereja pays a fine 8 times, so the answer is 3 - 8 = - 5.
import java.io.*;
import java.util.*;

public class Main
{
	public static void main(String[] args) throws IOException
	{
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		int d = in.nextInt();
		int[] a = new int[n];
		for(int i = 0; i < n; ++i)
			a[i] = in.nextInt();
		int m = in.nextInt();
		int result = 0;
		Arrays.sort(a);
		for(int i = 0; i < m && i < n; ++i)
			result += a[i];
		if(m > n)
			result -= d * (m - n);
		System.out.println(result);
	}
}



/////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////

class FunLib
{
	public static long gcd(long a, long b)
	{
		if(b == 0)
			return a;
		return gcd(b, a % b);
	}
	
	public static int gcd(int a, int b)
	{
		if(b == 0)
			return a;
		return gcd(b, a % b);
	}
	
	public static long lcm(long a, long b)
	{
		return a / gcd(a, b) * b;
	}
	
	public static int[][] transpose(int[][] mat)
	{
		int r = mat.length;
		int c = mat[0].length;
		int[][] result = new int[c][r];
		for(int i = 0; i < c; ++i)
			for(int j = 0; j < r; ++j)
				result[i][j] = mat[j][i];
		return result;
	}
}

abstract class AbstractSegTree
{
	public AbstractSegTree(int aSize)
	{
		size = aSize;
		storage = new int[4 * size];
	}
	
	public int getVal(int index)
	{
		return getValHelper(0, 0, size - 1, index);
	}
	
	public void rangeSet(int lower, int upper, int val)
	{
		rangeSetHelper(0, 0, size - 1, lower, upper, val);
	}
	
	protected abstract int getValHelper(int node, int beg, int end, int index);
	protected abstract void rangeSetHelper(int node, int beg, int end, int lower, int upper, int val);
	protected int[] storage;
	protected int size;
}


class Trie
{
	public Trie()
	{
		currentNode = root;
	}
	
	public void reset()
	{
		currentNode = root;
	}
	
	public void add(String word)
	{
		currentNode = root;
		for(int i = 0; i < word.length(); ++i)
		{
			// Only upper case characters
			int nodeIndex = word.charAt(i) - 'A';
			if(currentNode.children[nodeIndex] == null)
				currentNode.children[nodeIndex] = new Node();
			currentNode = currentNode.children[nodeIndex];
		}
		currentNode.isWord = true;
		currentNode = root;
	}
	
	public boolean feed(char c)
	{
		if(currentNode.children[c - 'A'] == null)
			return false;
		currentNode = currentNode.children[c - 'A'];
		return true;
	}
	
	public boolean isCurrentWord()
	{
		return currentNode.isWord;
	}
	
	private static class Node
	{
		public boolean isWord;
		// Only upper case characters
		public Node[] children = new Node[26];
	}
	
	private Node root = new Node();
	private Node currentNode;
}