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".

//package cf;


import java.io.*;
import java.util.*;

public class B {

    public static void main(String[] args) {
        BIO io = new BIO();
        try {
            Bsolver solver = new Bsolver(io);
        } finally {
            io.close();
        }
    }

}

class Bsolver {

    public Bsolver(BIO io) {
        int n = io.nextInt();
        ArrayList<Long> values = new ArrayList<>(n);
        for (int i=0; i<n; i++) {
            values.add(io.nextLong());
        }
        Collections.sort(values, Comparator.reverseOrder());
        HashSet<Long> taken = new HashSet<>();
        long count = 0;
        for (Long value : values) {
            while (taken.contains(value)) {
                value--;
            }
            if (value < 1) continue;
            taken.add(value);
            count += value;
        }
        
        io.println(count);
    }
    
}

class BIO extends PrintWriter {
    private InputStreamReader r;
    private static final int BUFSIZE = 1 << 15;
    private char[] buf;
    private int bufc;
    private int bufi;
    private StringBuilder sb;

    public BIO() {
            super(new BufferedOutputStream(System.out));
            r = new InputStreamReader(System.in);

            buf = new char[BUFSIZE];
            bufc = 0;
            bufi = 0;
            sb = new StringBuilder();
    }

    private void fillBuf() throws IOException {
            bufi = 0;
            bufc = 0;
            while(bufc == 0) {
                    bufc = r.read(buf, 0, BUFSIZE);
                    if(bufc == -1) {
                            bufc = 0;
                            return;
                    }
            }
    }

    private boolean pumpBuf() throws IOException {
            if(bufi == bufc) {
                    fillBuf();
            }
            return bufc != 0;
    }

    private boolean isDelimiter(char c) {
            return c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\f';
    }

    private void eatDelimiters() throws IOException {
            while(true) {
                    if(bufi == bufc) {
                            fillBuf();
                            if(bufc == 0) throw new RuntimeException("IO: Out of input.");
                    }

                    if(!isDelimiter(buf[bufi])) break;
                    ++bufi;
            }
    }

    public String next() {
            try {
                    sb.setLength(0);

                    eatDelimiters();
                    int start = bufi;

                    while(true) {
                            if(bufi == bufc) {
                                    sb.append(buf, start, bufi - start);
                                    fillBuf();
                                    start = 0;
                                    if(bufc == 0) break;
                            }

                            if(isDelimiter(buf[bufi])) break;
                            ++bufi;
                    }

                    sb.append(buf, start, bufi - start);

                    return sb.toString();
            } catch(IOException e) {
                    throw new RuntimeException("IO.next: Caught IOException.");
            }
    }

    public int nextInt() {
            try {
                    int ret = 0;

                    eatDelimiters();

                    boolean positive = true;
                    if(buf[bufi] == '-') {
                            ++bufi;
                            if(!pumpBuf()) throw new RuntimeException("IO.nextInt: Invalid int.");
                            positive = false;
                    }

                    boolean first = true;
                    while(true) {
                            if(!pumpBuf()) break;
                            if(isDelimiter(buf[bufi])) {
                                    if(first) throw new RuntimeException("IO.nextInt: Invalid int.");
                                    break;
                            }
                            first = false;

                            if(buf[bufi] >= '0' && buf[bufi] <= '9') {
                                    if(ret < -214748364) throw new RuntimeException("IO.nextInt: Invalid int.");
                                    ret *= 10;
                                    ret -= (int)(buf[bufi] - '0');
                                    if(ret > 0) throw new RuntimeException("IO.nextInt: Invalid int.");
                            } else {
                                    throw new RuntimeException("IO.nextInt: Invalid int.");
                            }

                            ++bufi;
                    }

                    if(positive) {
                            if(ret == -2147483648) throw new RuntimeException("IO.nextInt: Invalid int.");
                            ret = -ret;
                    }

                    return ret;
            } catch(IOException e) {
                    throw new RuntimeException("IO.nextInt: Caught IOException.");
            }
    }

    public long nextLong() {
            try {
                    long ret = 0;

                    eatDelimiters();

                    boolean positive = true;
                    if(buf[bufi] == '-') {
                            ++bufi;
                            if(!pumpBuf()) throw new RuntimeException("IO.nextLong: Invalid long.");
                            positive = false;
                    }

                    boolean first = true;
                    while(true) {
                            if(!pumpBuf()) break;
                            if(isDelimiter(buf[bufi])) {
                                    if(first) throw new RuntimeException("IO.nextLong: Invalid long.");
                                    break;
                            }
                            first = false;

                            if(buf[bufi] >= '0' && buf[bufi] <= '9') {
                                    if(ret < -922337203685477580L) throw new RuntimeException("IO.nextLong: Invalid long.");
                                    ret *= 10;
                                    ret -= (long)(buf[bufi] - '0');
                                    if(ret > 0) throw new RuntimeException("IO.nextLong: Invalid long.");
                            } else {
                                    throw new RuntimeException("IO.nextLong: Invalid long.");
                            }

                            ++bufi;
                    }

                    if(positive) {
                            if(ret == -9223372036854775808L) throw new RuntimeException("IO.nextLong: Invalid long.");
                            ret = -ret;
                    }

                    return ret;
            } catch(IOException e) {
                    throw new RuntimeException("IO.nextLong: Caught IOException.");
            }
    }

    public double nextDouble() {
            return Double.parseDouble(next());
    }

}