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.math.BigDecimal;
import java.math.BigInteger;
import java.security.KeyPair;
import java.util.*;
import java.io.*;
import java.lang.*;

public class A implements Runnable {
    long mod = (long) 1e9 + 7;

    void solve(InputReader in, PrintWriter w) {
        int t = 1;
//        t = in.nextInt();
//        in.nextLine();
        while (t-- != 0)
            play(in, w);
    }

    public static void play(InputReader in, PrintWriter w) {
        int n = in.nextInt();
        int d = in.nextInt();
        int[] a = new int[n];
        for (int i = 0; i < n; ++i) {
            a[i] = in.nextInt();
        }
        Arrays.sort(a);
        long profit = 0;
        int m = in.nextInt();
        if (m <= n) {
            for (int i = 0; i < m; ++i) {
                profit += a[i];
            }
            w.println(profit);
            return;
        } else {
            for (int i = 0; i < n; ++i) {
                profit += a[i];
            }
        }
        w.println(profit - (m - n) * d);
    }

    public static class pair {
        private long key;
        private long val;

        public pair(long key, long val) {
            this.key = key;
            this.val = val;
        }

        public long getKey() {
            return key;
        }

        public long getVal() {
            return val;
        }
        //
//    @Override
//    public String toString() {
//        return val+"["
//    }
    }

    public static int[] sieve() {
        int n = 1000010;
        int limit = (int) Math.sqrt(n);
        int[] a = new int[n + 10];
        a[1] = 1;
        for (int i = 2; i <= limit; i++) {
            if (a[i] == 0) {
                for (int j = i * i; j <= n; j += i) {
                    a[j] = 1;
                }
            }
        }
        return a;
    }

    // ************* Code ends here ***************
    void init() throws Exception {
        //Scanner in;
        InputReader in;
        PrintWriter w;
        boolean online = false;
        String common_in_fileName = "\\in";
        String common_out_fileName = "\\out";
        int test_files = 0;
        for (int file_no = 0; file_no <= test_files; file_no++) {
            String x = "" + file_no;
            if (x.length() == 1) x = "0" + x;
            String in_fileName = common_in_fileName + "" + x;
            String out_fileName = common_out_fileName + "" + x;
            if (online) {
                //in = new Scanner(new File(in_fileName + ".txt"));
                in = new InputReader(new FileInputStream(new File(in_fileName + ".txt")));
                w = new PrintWriter(new FileWriter(out_fileName + ".txt"));
            } else {
                //in = new Scanner(System.in);
                in = new InputReader(System.in);
                w = new PrintWriter(System.out);
            }

            solve(in, w);
            w.close();
        }
    }

    public void run() {
        try {
            init();
        } catch (Exception e) {
            System.out.println(e);
            e.printStackTrace();
        }
    }

    public static void main(String args[]) throws Exception {
        new Thread(null, new A(), "Sol", 1 << 28).start();
    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public 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++];
        }

        public String nextLine() {
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }

        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 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 double nextDouble() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            double res = 0;
            while (!isSpaceChar(c) && c != '.') {
                if (c == 'e' || c == 'E') {
                    return res * Math.pow(10, nextInt());
                }
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            }
            if (c == '.') {
                c = read();
                double m = 1;
                while (!isSpaceChar(c)) {
                    if (c == 'e' || c == 'E') {
                        return res * Math.pow(10, nextInt());
                    }
                    if (c < '0' || c > '9') {
                        throw new InputMismatchException();
                    }
                    m /= 10;
                    res += (c - '0') * m;
                    c = read();
                }
            }
            return res * sgn;
        }

        public String readString() {
            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 boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public String next() {
            return readString();
        }

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