You are given an alphabet consisting of n letters, your task is to make a string of the maximum possible length so that the following conditions are satisfied: 

  * the i-th letter occurs in the string no more than ai times; 
  * the number of occurrences of each letter in the string must be distinct for all the letters that occurred in the string at least once. 

Input

The first line of the input contains a single integer n (2 ≤ n ≤ 26) — the number of letters in the alphabet.

The next line contains n integers ai (1 ≤ ai ≤ 109) — i-th of these integers gives the limitation on the number of occurrences of the i-th character in the string.

Output

Print a single integer — the maximum length of the string that meets all the requirements.

Examples

Input

3
2 5 5


Output

11


Input

3
1 1 2


Output

3

Note

For convenience let's consider an alphabet consisting of three letters: "a", "b", "c". In the first sample, some of the optimal strings are: "cccaabbccbb", "aabcbcbcbcb". In the second sample some of the optimal strings are: "acc", "cbc".
import java.util.*;
import java.io.*;
public class MakingAString
{

	/************************ SOLUTION STARTS HERE ************************/

	//DONT FORGET TO COMMIT AND PUSH TO GITHUB

	private static void solve(FastScanner s1, FastWriter out){

		int n = s1.nextInt();
		int arr[] = s1.nextIntArray(n);
		Arrays.sort(arr);
		HashSet<Integer> set = new HashSet<>();		
		for(int a:arr)
		{
			if(!set.contains(a))
				set.add(a);
			else
			{
				while(a>0 && set.contains(a))	
					a--;
				if(a>0)
					set.add(a);
			}
		}
		long len = 0;
		for(int a:set)
			len += (long)a;
		//out.print(set);
		out.print(len);
	}

	/************************ SOLUTION ENDS HERE ************************/



	/************************ TEMPLATE STARTS HERE ************************/

	public static void main(String []args) throws IOException {
		FastScanner in  = new FastScanner(System.in);
		FastWriter  out = new FastWriter(System.out);
		solve(in, out);
		in.close();
		out.close();
	}    

	static class FastScanner{
		public BufferedReader reader;
		public StringTokenizer st;
		public FastScanner(InputStream stream){
			reader = new BufferedReader(new InputStreamReader(stream));
			st = null;
		}
		public String next(){
			while(st == null || !st.hasMoreTokens()){
				try{
					String line = reader.readLine();
					if(line == null) return null;
					st = new StringTokenizer(line);
				}catch (Exception e){
					throw (new RuntimeException());
				}
			}
			return st.nextToken();
		}
		public String nextLine(){
			String str = null;
			try {
				str = reader.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
		public int nextInt(){
			return Integer.parseInt(next());
		}
		public long nextLong(){
			return Long.parseLong(next());
		}
		public double nextDouble(){
			return Double.parseDouble(next());
		}
		int[] nextIntArray(int n) {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextInt();
			}
			return arr;
		}

		long[] nextLongArray(int n) {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		}
		public void close(){	
			try{ reader.close(); } catch(IOException e){e.printStackTrace();}
		}
	}
	static class FastWriter{
		BufferedWriter writer;
		public FastWriter(OutputStream stream){
			writer = new BufferedWriter(new OutputStreamWriter(stream));
		}
		public void print(int i) {
			print(Integer.toString(i));
		}
		public void println(int i) {
			print(Integer.toString(i));
			print('\n');
		}
		public void print(long i) {
			print(Long.toString(i));
		}
		public void println(long i) {
			print(Long.toString(i));
			print('\n');
		}
		public void print(double i) {
			print(Double.toString(i));
		}
		public void print(boolean i) {
			print(Boolean.toString(i));
		}
		public void print(Object o){
			print(o.toString());
		}
		public void println(Object o){
			print(o.toString());
			print('\n');
		}
		public void print(char i) {
			try{writer.write(i);} catch(IOException e){e.printStackTrace();}
		}
		public void print(String s){
			try{writer.write(s);} catch(IOException e){e.printStackTrace();}
		}
		public void println(String s){
			try{writer.write(s);writer.write('\n');} catch(IOException e){e.printStackTrace();}
		}
		public void println(){
			try{writer.write('\n');} catch(IOException e){e.printStackTrace();}
		}
		public void print(int arr[])
		{
			for (int i = 0; i < arr.length; i++) {
				print(arr[i]);
				print(' ');
			}
		}
		public void close(){
			try{writer.close();} catch(IOException e){e.printStackTrace();}
		}
	}

	/************************ TEMPLATE ENDS HERE ************************/
}
