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.Arrays;
import java.util.InputMismatchException;

/**
 * 
 * @author Code Forces.  Solution by: L.Azuaje.
 *
 * Problem: .
 *
 *
 */

public class Main {
	public static void main(String[] args) throws IOException {
		MyScanner scanner = new MyScanner();
		PrintStream out = System.out;

        int[] data = scanner.nextIntArray();
        int[] prices = scanner.nextIntArray();
        int guests = scanner.nextInt();
        int total = 0;

        Arrays.sort(prices);

        int capacity = data[0];
        int fine = data[1];

        if (guests <= prices.length) {
            for (int i = 0; i < guests; i++) {
                total += prices[i];
            }
        } else {
            for (int i = 0; i < prices.length; i++) {
                total += prices[i];
            }
            total +=  - fine * (guests - prices.length);
        }

		out.println(total);

		scanner.close();
		out.close();
	}

	// -----------MyScanner class for faster input----------
    public static class FastInputReader {
        private byte[] buf = new byte[16384];
        private int    curChar;
        private int    numChars;

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

        public 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();
        }

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

        public 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;
        }

        public 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;
        }

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

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

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

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

	public static class MyScanner {
		BufferedReader reader;

		public MyScanner() {
			this.reader = new BufferedReader(new InputStreamReader(System.in));
		}

		public void close() throws IOException {
			this.reader.close();
		}

		int nextInt() {
			return Integer.parseInt(this.next());
		}

		long nextLong() {
			return Long.parseLong(this.next());
		}

        float nextFloat() {
            return Float.parseFloat(this.next());
        }

        double nextDouble() {
            return Double.parseDouble(this.next());
        }

        String next() {
			String str = "";
			try {
				str = this.reader.readLine().trim();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}

		String[] nextStringArray() {
			String[] str = null;
			try {
				str = this.reader.readLine().trim().split(" ");
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}

		int[] nextIntArray() {
			String[] data  = nextStringArray();
			int[] a  = new int[data.length];

			for (int i = 0; i < a.length; i++) {
				a[i] = Integer.parseInt(data[i]);
			}

			return a;
		}

		Integer[] nextIntegerArray() {
			String[] data  = nextStringArray();
			Integer[] a  = new Integer[data.length];

			for (int i = 0; i < a.length; i++) {
				a[i] = Integer.parseInt(data[i]);
			}

			return a;
		}

		long[] nextLongArray() {
			String[] data  = nextStringArray();
			long[] a  = new long[data.length];

			for (int i = 0; i < a.length; i++) {
				a[i] = Long.parseLong(data[i]);
			}

			return a;
		}

        float[] nextFloatArray() {
            String[] data  = nextStringArray();
            float[] a  = new float[data.length];

            for (int i = 0; i < a.length; i++) {
                a[i] = Float.parseFloat(data[i]);
            }

            return a;
        }

        double[] nextDoubleArray() {
            String[] data  = nextStringArray();
            double[] a  = new double[data.length];

            for (int i = 0; i < a.length; i++) {
                a[i] = Double.parseDouble(data[i]);
            }

            return a;
        }
    }
}

