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.io.*;
import java.math.BigInteger;
import java.util.*;

import static java.lang.Math.PI;
import static java.lang.System.in;
import static java.lang.System.out;
import static java.lang.System.err;

public class C { 
    public static void main(String[] args) throws Exception {   
        Foster sc = new Foster();
        PrintWriter p = new PrintWriter(out);
        int n = sc.nextInt();
        int a[] = sc.intArray(n);
        a = sort(a);
        TreeSet<Integer> tree = new TreeSet<>();
        long sum = 0;
        for(int i = n-1; i >= 0; i--){
            if(!tree.contains(a[i]) && a[i] != 0){
                sum += a[i];
                tree.add(a[i]);
            }
            else{
                int small = 0;
                for(int k : tree){
                    small = k;
                    break;
                }
                if(a[i] >= small && a[i] > 1){
                    if(small-1 > 0){
                        tree.add(small-1);
                        sum += (small-1);
                    }
                }
            }
        }
        p.println(sum);
        p.close();
    }

    static int[] sort(int a[]){
        ArrayList<Integer> arr = new ArrayList<>();
        for(int i : a){
            arr.add(i);
        }
        Collections.sort(arr);
        for(int i = 0; i < arr.size(); i++){
            a[i] = arr.get(i);
        }
        return a;
    }
    
/* 
    3
    5 5 4 3
*/    
/*
1. Check overflow in pow function or in general
2. Check indices of read array function
3. Think of an easier solution because the problems you solve are always easy
4. Check iterator of loop
5. If still doesn't work, then jump from the 729th floor 'coz "beta tumse na ho paayega"

    Move to top!!
*/
    static class Foster {
        BufferedReader br = new BufferedReader(new InputStreamReader(in));
        StringTokenizer st = new StringTokenizer("");
        String next() {
            while (!st.hasMoreTokens())
                try {
                    st = new StringTokenizer(br.readLine());
                } 
                catch (IOException e) {
                    e.printStackTrace();
                }
            return st.nextToken();
        }
        int nextInt() {
            return Integer.parseInt(next());
        }
        long nextLong() {
            return Long.parseLong(next());
        }
        double nextDouble() {
            return Double.parseDouble(next());
        }
        int[] intArray(int n) {                   // Check indices
            int arr[] = new int[n];
            for(int i = 0; i < n; i++) {
                arr[i] = nextInt();
            }
            return arr;
        }
        long[] longArray(int n) {                 // Check indices
            long arr[] = new long[n];
            for(int i = 0; i < n; i++) {
                arr[i] = nextLong();
            }
            return arr;
        }
        int[] getBits(int n) {                   //in Reverse Order
            int a[] = new int[31];
            for(int i = 0; i < 31; i++) {
                if(((1<<i) & n) != 0)
                    a[i] = 1;
            }
            return a;
        }
        static String reverse(String s){
            String temp = "";
            for(int i = s.length()-1; i >= 0; i--){
                temp += s.charAt(i);
            }
            return temp;
        }
        static long pow(long... a) {
            long mod = Long.MAX_VALUE;
            if(a.length == 3)   mod = a[2];
            long res = 1;
            while(a[1] > 0) {
                if((a[1] & 1) == 1)
                    res = (res * a[0]) % mod;
                a[1] /= 2;
                a[0] = (a[0] * a[0]) % mod;
            }
            return res;
        }
        static void print(Object... o) {
            for(Object next : o) {
                System.err.print(next + " ");
            }
        }
        static void println(Object... o) {
            for(Object next : o) {
                System.err.print(next + " ");
            }
            System.err.println();
        }
        static void watch(Object...a) throws Exception {
            int i = 1;
            for (Object o: a) {
                boolean found = false;
                if (o.getClass().isArray()) {
                    String type = o.getClass().getName().toString();
                    switch (type) {
                        case "[I": {
                            int[] test = (int[]) o;
                            println(i + " : " + Arrays.toString(test));
                            break;
                        }
                        case "[[I": {
                            int[][] obj = (int[][]) o;
                            println(i + " : " + Arrays.deepToString(obj));
                            break;
                        }
                        case "[J": {
                            long[] obj = (long[]) o;
                            println(i + " : " + Arrays.toString(obj));
                            break;
                        }
                        case "[[J": {
                            long[][] obj = (long[][]) o;
                            println(i + " : " + Arrays.deepToString(obj));
                            break;
                        }
                        case "[D": {
                            double[] obj = (double[]) o;
                            println(i + " : " + Arrays.toString(obj));
                            break;
                        }
                        case "[[D": {
                            double[][] obj = (double[][]) o;
                            println(i + " : " + Arrays.deepToString(obj));
                            break;
                        }
                        case "[Ljava.lang.String": {
                            String[] obj = (String[]) o;
                            println(i + " : " + Arrays.toString(obj));
                            break;
                        }
                        case "[[Ljava.lang.String": {
                            String[][] obj = (String[][]) o;
                            println(i + " : " + Arrays.deepToString(obj));
                            break;
                        }
                        case "[C": {
                            char[] obj = (char[]) o;
                            println(i + " : " + Arrays.toString(obj));
                            break;
                        }
                        case "[[C": {
                            char[][] obj = (char[][]) o;
                            println(i + " : " + Arrays.deepToString(obj));
                            break;
                        }
                        default: {
                            println(i + " : type not identified");
                            break;
                        }
                    }
                    found = true;
                }
                if (o.getClass() == ArrayList.class) {
                    println(i + " : LIST = " + o);
                    found = true;
                }
                if (o.getClass() == TreeSet.class) {
                    println(i + " : SET = " + o);
                    found = true;
                }
                if (o.getClass() == TreeMap.class) {
                    println(i + " : MAP = " + o);
                    found = true;
                }
                if (o.getClass() == HashMap.class) {
                    println(i + " : MAP = " + o);
                    found = true;
                }
                if (o.getClass() == LinkedList.class) {
                    println(i + " : LIST = " + o);
                    found = true;
                }
                if (o.getClass() == PriorityQueue.class) {
                    println(i + " : PQ = " + o);
                    found = true;
                }
                if (!found) {
                    println(i + " = " + o);
                }
                i++;
            }
        }
    }
}