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.util.*;
import java.util.stream.Collectors;

public class Main {

    public static void main(String[] args) throws IOException {
        IO io = new IO() ;
        int n = io.getInt();
        long ans = 0 ;
        List<Integer> nums = io.getIntegerArray(n) ;
        Set<Integer> s = new HashSet<>() ;

        for(int a: nums){
            while(a != 0 && s.contains(a)){
                a-- ;
            }
            s.add(a) ;
            ans += a ;
        }
        System.out.println(ans);
    }
}

class Utils {

    static int[][] fourDirs = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}} ;
    static int[][] eightDirs = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}, {1, 1}, {1, -1}, {-1, 1}, {-1, -1}} ;

    public static List<Integer> sieve(int n){
        boolean b[] = new boolean[n + 1] ;
        List<Integer> ans = new ArrayList<>() ;
        Arrays.fill(b, true) ;

        for(int i = 2 ; i <= n ; i++){
            if(b[i]){
                ans.add(i) ;
                for(int j = i*i ; j >= 0 && j <= n ; j += i){
                    b[j] = false ;
                }
            }
        }
        return ans ;
    }

    public static boolean isPrime(long n){
        long sqrt = (long)Math.sqrt(n) ;
        for(int i = 2 ; i <= sqrt ; i++){
            if(n % i == 0)
                return false ;
        }
        return true ;
    }

    public static long mod(long n){
        if(n > 0)
            return n % 1000000007 ;
        return (n + 2000000014) % 1000000007 ;
    }

    public static boolean isSqr(long n){
        int sqrt = (int) Math.sqrt(n) ;
        return n == (long)sqrt*sqrt ;
    }

    public static Utils.Pair getSlope(int x0, int y0, int x1, int y1){
        int a = y1 - y0, b = x1 - x0, g = (int)Utils.gcd(Math.abs(a), Math.abs(b)) ;
        if(g != 0){
            a /= g ;
            b /= g ;
        }
        if(a < 0){
            a *= -1 ;
            b *= -1 ;
        }
        else if(a == 0){
            b = 1 ;
        }
        return new Utils.Pair(a, b) ;
    }

    public static boolean inRange(long i, long l, long h){
        return i >= l && i <= h ;
    }

    public static boolean isValid(int i, int j, int n, int m){
        return i >= 0 && j >= 0 && i < n && j < m ;
    }

    public static void swap(List<Integer> ls, int i, int j){
        int temp = ls.get(i) ;
        ls.set(i, ls.get(j)) ;
        ls.set(j, temp) ;
    }

    public static long gcd(long a, long b){
        if(a < b)
            return gcd(b, a) ;
        else if(a == b || b == 0)
            return a ;
        else{
            return gcd(b, a % b) ;
        }
    }

    public static long subSum(long[] pre, int l, int h){
        return l == 0 ? pre[h]: pre[h] - pre[l - 1] ;
    }

    public static class Pair implements Comparable<Pair>{
        public int l, h ;

        public Pair(int a, int b) {
            this.l = a;
            this.h = b;
        }

        @Override
        public int compareTo(Pair o) {
            return l - o.l ;
        }

        @Override
        public String toString() {
            return "Pair{" +
                    "l=" + l +
                    ", h=" + h +
                    '}';
        }

        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;

            Pair pair = (Pair) o;

            if (l != pair.l) return false;
            return h == pair.h;
        }

        @Override
        public int hashCode() {
            int result = l;
            result = 31 * result + h;
            return result;
        }
    }

    public static void ifPrint(boolean test, Object ifValue, Object elseValue){
        System.out.println(test ? ifValue: elseValue) ;
    }

    public static void print(Character delim, Object... a){
        List<String> top = new ArrayList<>() ;
        for(Object aa: a)
            top.add(aa == null ? "null": aa.toString()) ;
        System.out.println(join(top, delim.toString())) ;
    }

    public static void print(Object... a){
        print(' ', a) ;
    }

    public static  <T extends Comparable<T>> int lowerBound(T[] arr, int l, int h, T key){
        while(l < h){
            int mid = (l + h) / 2 ;
            if(arr[mid].compareTo(key) < 0)
                l = mid + 1 ;
            else
                h = mid ;
        }
        return arr[l].compareTo(key) >= 0 ? l: -1 ;
    }

    public static <T extends Comparable<T>> int upperBound(T[] arr, int l, int h, T key){
        while(l < h){
            int mid = (l + h) / 2 ;
            if(arr[mid].compareTo(key) < 0)
                l = mid + 1 ;
            else if(arr[mid].compareTo(key) == 0)
                l = mid ;
            else
                h = mid ;
            if(h == l + 1)
                break ;
        }
        return arr[l].compareTo(key) >= 0 ? l: -1 ;
    }

    public static class IndexedElement<T> {
        int idx;
        T val;

        public IndexedElement(int idx, T val) {
            this.idx = idx;
            this.val = val;
        }

        @Override
        public String toString() {
            return "IndexedElement{" +
                    "idx=" + idx +
                    ", val=" + val +
                    '}';
        }
    }

    public static <T> ArrayList<IndexedElement<T>> getIndexedArray(List<T> ip) {
        ArrayList<IndexedElement<T>> op = new ArrayList<>();
        for (int i = 0; i < ip.size(); i++) {
            op.add(new IndexedElement<>(i, ip.get(i)));
        }
        return op;
    }

    public static <T> String join(List<T> ls) {
        return join(ls, " ") ;
    }

    public static <T> String join(List<T> ls, String delim) {
        StringJoiner sj = new StringJoiner(delim);
        for (T a : ls)
            sj.add(a.toString());
        return sj.toString();
    }

    public static <T> void print2DArray(List<List<T>> mat) {
        for (List<T> m : mat) {
            System.out.println("{ " + join(m, ", ") + " }");
        }
    }

    public static  <T> void reverseArrray(T[] arr, int l, int h){
        while(l < h){
            T temp = arr[l] ;
            arr[l] = arr[h] ;
            arr[h] = temp ;
            l++ ;
            h-- ;
        }
    }
}

class IO {
    private BufferedReader br = null;
    private StringTokenizer st = null;

    public IO() {
        this(System.in);
    }

    public IO(InputStream is) {
        this.br = new BufferedReader(new InputStreamReader(is));
    }

    public List<String> getStringArray(int n) throws IOException {
        if (n == 0)
            return new ArrayList<>();
        if (st == null || !st.hasMoreTokens())
            st = new StringTokenizer(br.readLine());
        List<String> res = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            if (!st.hasMoreTokens())
                st = new StringTokenizer(br.readLine());
            res.add(st.nextToken());
        }
        return res;
    }
    public String getString() throws IOException {
        List<String> res = this.getStringArray(1);
        return res.size() == 0 ? "" : res.get(0);
    }

    public List<Integer> getIntegerArray(int n) throws IOException {
        if (n == 0)
            return new ArrayList<>();
        List<String> res = getStringArray(n);
        return res.stream().map(Integer::parseInt).collect(Collectors.toList());
    }
    public Integer getInt() throws IOException {
        List<Integer> res = this.getIntegerArray(1);
        return res.size() == 0 ? 0 : res.get(0);
    }

    public List<Long> getLongArray(int n) throws IOException {
        if (n == 0)
            return new ArrayList<>();
        List<String> res = getStringArray(n);
        return res.stream().map(Long::parseLong).collect(Collectors.toList());
    }
    public Long getLong() throws IOException {
        List<Long> res = this.getLongArray(1);
        return res.size() == 0 ? 0L : res.get(0);
    }

    public List<Double> getDoubleArray(int n) throws IOException {
        if (n == 0)
            return new ArrayList<>();
        List<String> res = getStringArray(n);
        return res.stream().map(Double::parseDouble).collect(Collectors.toList());
    }
    public Double getDouble() throws IOException {
        List<Double> res = this.getDoubleArray(1);
        return res.size() == 0 ? 0.0 : res.get(0);
    }
}