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.File;import java.io.FileInputStream;import java.io.FileNotFoundException;
import java.io.IOException;import java.io.PrintStream;import java.io.PrintWriter;
import java.security.AccessControlException;import java.util.Arrays;import java.util.Collection;
import java.util.Comparator;import java.util.List;import java.util.Map;import java.util.Objects;
import java.util.Scanner;import java.util.TreeMap;import java.util.function.Function;
import java.util.stream.Collectors;import java.util.stream.IntStream;import java.util.stream.LongStream;
import java.util.stream.Stream;public class _p000368A {static public void main(final String[] args) 
throws IOException{p000368A._main(args);}
static private class p000368A extends Solver{public p000368A(){nameIn="in/1000/p000368A.in";
singleTest=true;}@Override public void solve()throws IOException{int n=sc.nextInt();
int d=sc.nextInt();sc.nextLine();int[]a=lineToIntArray();int m=sc.nextInt();sc.nextLine();
int res=0;if(m<n){Arrays.sort(a);res=Arrays.stream(a,0,m).sum();}else{res=Arrays.stream(a).sum()
-d*(m-n);}pw.println(res);}static public void _main(String[]args)throws IOException
{new p000368A().run();}}static private class Pair<K,V>{private K k;private V v;public 
Pair(final K t,final V u){this.k=t;this.v=u;}public K getKey(){return k;}public 
V getValue(){return v;}}static private abstract class Solver{protected String nameIn
=null;protected String nameOut=null;protected boolean singleTest=false;protected 
boolean preprocessDebug=false;protected boolean doNotPreprocess=false;protected 
PrintStream debugPrintStream=null;protected Scanner sc=null;protected PrintWriter 
pw=null;final static String SPACE=" ";final static String SPACES="\\s+";private 
void process()throws IOException{if(!singleTest){int t=lineToIntArray()[0];while(t--
>0){solve();pw.flush();}}else{solve();pw.flush();}}abstract protected void solve()
throws IOException;protected String[]lineToArray()throws IOException{return sc.nextLine().trim().split(SPACES);
}protected int[]lineToIntArray()throws IOException{return Arrays.stream(lineToArray()).mapToInt(Integer::valueOf).toArray();
}protected long[]lineToLongArray()throws IOException{return Arrays.stream(lineToArray()).mapToLong(Long::valueOf).toArray();
}protected void run()throws IOException{boolean done=false;try{if(nameIn!=null && 
new File(nameIn).exists()){try(FileInputStream fis=new FileInputStream(nameIn);PrintWriter 
pw0=select_output();){done=true;sc=new Scanner(fis);pw=pw0;process();}}}catch(IOException 
ex){}catch(AccessControlException ex){}if(!done){try(PrintWriter pw0=select_output();
){sc=new Scanner(System.in);pw=pw0;process();}}}private PrintWriter select_output()
throws FileNotFoundException{if(nameOut!=null){return new PrintWriter(nameOut);}
return new PrintWriter(System.out);}public static Map<Integer,List<Integer>>mapi(final 
int[]a){return IntStream.range(0,a.length).collect(()->new TreeMap<Integer,List<Integer>>(),
(res,i)->{if(!res.containsKey(a[i])){res.put(a[i],Stream.of(i).collect(Collectors.toList()));
}else{res.get(a[i]).add(i);}},Map::putAll);}public static Map<Long,List<Integer>>
mapi(final long[]a){return IntStream.range(0,a.length).collect(()->new TreeMap<Long,
List<Integer>>(),(res,i)->{if(!res.containsKey(a[i])){res.put(a[i],Stream.of(i).collect(Collectors.toList()));
}else{res.get(a[i]).add(i);}},Map::putAll);}public static<T>Map<T,List<Integer>>
mapi(final T[]a){return IntStream.range(0,a.length).collect(()->new TreeMap<T,List<Integer>>(),
(res,i)->{if(!res.containsKey(a[i])){res.put(a[i],Stream.of(i).collect(Collectors.toList()));
}else{res.get(a[i]).add(i);}},Map::putAll);}public static<T>Map<T,List<Integer>>
mapi(final T[]a,Comparator<T>cmp){return IntStream.range(0,a.length).collect(()->
new TreeMap<T,List<Integer>>(cmp),(res,i)->{if(!res.containsKey(a[i])){res.put(a[i],
Stream.of(i).collect(Collectors.toList()));}else{res.get(a[i]).add(i);}},Map::putAll
);}public static Map<Integer,List<Integer>>mapi(final IntStream a){int[]i=new int[]{0};
return a.collect(()->new TreeMap<Integer,List<Integer>>(),(res,v)->{if(!res.containsKey(v))
{res.put(v,Stream.of(i[0]).collect(Collectors.toList()));}else{res.get(v).add(i[0]);
}i[0]++;},Map::putAll);}public static Map<Long,List<Integer>>mapi(final LongStream 
a){int[]i=new int[]{0};return a.collect(()->new TreeMap<Long,List<Integer>>(),(res,
v)->{if(!res.containsKey(v)){res.put(v,Stream.of(i[0]).collect(Collectors.toList()));
}else{res.get(v).add(i[0]);}i[0]++;},Map::putAll);}public static<T>Map<T,List<Integer>>
mapi(final Stream<T>a,Comparator<T>cmp){int[]i=new int[]{0};return a.collect(()->
new TreeMap<T,List<Integer>>(cmp),(res,v)->{if(!res.containsKey(v)){res.put(v,Stream.of(i[0]).collect(Collectors.toList()));
}else{res.get(v).add(i[0]);}},Map::putAll);}public static<T>Map<T,List<Integer>>
mapi(final Stream<T>a){int[]i=new int[]{0};return a.collect(()->new TreeMap<T,List<Integer>>(),
(res,v)->{if(!res.containsKey(v)){res.put(v,Stream.of(i[0]).collect(Collectors.toList()));
}else{res.get(v).add(i[0]);}},Map::putAll);}public static List<int[]>listi(final 
int[]a){return IntStream.range(0,a.length).mapToObj(i->new int[]{a[i],i}).collect(Collectors.toList());
}public static List<long[]>listi(final long[]a){return IntStream.range(0,a.length).mapToObj(i
->new long[]{a[i],i}).collect(Collectors.toList());}public static<T>List<Pair<T,
Integer>>listi(final T[]a){return IntStream.range(0,a.length).mapToObj(i->new Pair<T,
Integer>(a[i],i)).collect(Collectors.toList());}public static List<int[]>listi(final 
IntStream a){int[]i=new int[]{0};return a.mapToObj(v->new int[]{v,i[0]++}).collect(Collectors.toList());
}public static List<long[]>listi(final LongStream a){int[]i=new int[]{0};return 
a.mapToObj(v->new long[]{v,i[0]++}).collect(Collectors.toList());}public static<T>
List<Pair<T,Integer>>listi(final Stream<T>a){int[]i=new int[]{0};return a.map(v->
new Pair<T,Integer>(v,i[0]++)).collect(Collectors.toList());}public static String 
join(final int[]a){return Arrays.stream(a).mapToObj(Integer::toString).collect(Collectors.joining(SPACE));
}public static String join(final long[]a){return Arrays.stream(a).mapToObj(Long::toString).collect(Collectors.joining(SPACE));
}public static<T>String join(final T[]a){return Arrays.stream(a).map(v->Objects.toString(v)).collect(Collectors.joining(SPACE));
}public static<T>String join(final T[]a,final Function<T,String>toString){return 
Arrays.stream(a).map(v->toString.apply(v)).collect(Collectors.joining(SPACE));}public 
static<T>String join(final Collection<T>a){return a.stream().map(v->Objects.toString(v)).collect(Collectors.joining(SPACE));
}public static<T>String join(final Collection<T>a,final Function<T,String>toString)
{return a.stream().map(v->toString.apply(v)).collect(Collectors.joining(SPACE));
}public static<T>String join(final Stream<T>a){return a.map(v->Objects.toString(v)).collect(Collectors.joining(SPACE));
}public static<T>String join(final Stream<T>a,final Function<T,String>toString){
return a.map(v->toString.apply(v)).collect(Collectors.joining(SPACE));}public static
<T>String join(final IntStream a){return a.mapToObj(Integer::toString).collect(Collectors.joining(SPACE));
}public static<T>String join(final LongStream a){return a.mapToObj(Long::toString).collect(Collectors.joining(SPACE));
}public static List<Integer>list(final int[]a){return Arrays.stream(a).mapToObj(Integer::valueOf).collect(Collectors.toList());
}public static List<Integer>list(final IntStream a){return a.mapToObj(Integer::valueOf).collect(Collectors.toList());
}public static List<Long>list(final long[]a){return Arrays.stream(a).mapToObj(Long::valueOf).collect(Collectors.toList());
}public static List<Long>list(final LongStream a){return a.mapToObj(Long::valueOf).collect(Collectors.toList());
}public static<T>List<T>list(final Stream<T>a){return a.collect(Collectors.toList());
}public static<T>List<T>list(final T[]a){return Arrays.stream(a).collect(Collectors.toList());
}}}
