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.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;
import java.util.Set;



 
public class george
{
	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();
        }
    }
 static int max(int a[],int n) {
	 int max=a[0];
	 int ind=0;
	 for(int i=1;i<n;i++) {
		 if(a[i]>=max) {
			 max=a[i];
			 ind=i;
		 }
	 }
	 return ind;
 }
 static int min(int a[],int n) {
	 int min=a[0];
	 int ind=0;
	 for(int i=1;i<n;i++) {
		 if(a[i]<min) {
			 min=a[i];
			 ind=i;
		 }
	 }
	 return ind;
 }
 static boolean fun(int i) {
	 for(int j=3;j<=20;j++) {
		 if(i%j!=0) {
			 return false;
		 }
	 }
	 return true;
 }
 static int bin(int arr[], int l, int r, int x)
 {
     if (r>=l)
     {
         int mid = l + (r - l)/2;

       
         if (arr[mid] == x)
            return mid;

       
         if (arr[mid] > x)
            return bin(arr, l, mid-1, x);
         return bin(arr, mid+1, r, x);
     }


     return -1;
 }
 static boolean isPalindrome(int n)
 {   
     
     int divisor = 1;
     while (n / divisor >= 10)
         divisor *= 10;
   
     while (n != 0)
     {
         int leading = n / divisor; 
         int trailing = n % 10;
   
         if (leading != trailing)  
             return false;
   
         n = (n % divisor) / 10;
   
         divisor = divisor / 100;
     }
     return true;
 }
 public static String sortString(String inputString) 
 { 
     // convert input string to char array 
     char tempArray[] = inputString.toCharArray(); 
       
     // sort tempArray 
     Arrays.sort(tempArray); 
       
     // return new sorted string 
     return new String(tempArray); 
 } 
 public static boolean allDifferent( int[]a){
	    for(int i = 0; i < a.length; i++){
	        if(a[i] != 0){
	            return true;
	        }
	         
	    }
	    return false;
}

    public static void main(String[] args) throws IOException
    {
        Reader s=new Reader();
        int n = s.nextInt();
        int d = s.nextInt();
        int arr[]=new int[n];
        int pro=0;
        for(int i=0;i<n;i++) {
        	arr[i]=s.nextInt();
        }
        int m=s.nextInt();
        int k=0;
        if(m>n) {
        	k=n;
        	m-=n;
        	} else {
        	k=m;
        	m=0;
        	}
        Arrays.sort(arr); 
        for(int i=0;i<k;i++) {       
    		pro+=arr[i];
         }
        System.out.println(pro-(m*d));
    }
}