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.math.*;

public class Main implements Runnable {
    public InputReader in;
    public PrintWriter out;

    public void solve() throws Exception {
        // solution goes here
        int N = in.nextInt();
        int[] nums = in.nextInts(N);

        Arrays.sort(nums);
        for (int i = 0; i < nums.length / 2; i++) {
            int temp = nums[i];
            nums[i] = nums[nums.length - 1 - i];
            nums[nums.length - 1 - i] = temp;
        }


        for (int i = 0; i < nums.length; i++)
            while (i > 0 && nums[i] >= nums[i-1])
                nums[i]--;

        long total = 0;
        for(int num : nums)
            if (num > 0)
                total += num;

        out.print(total);
    }

    public void run() {
        try {
            in = new InputReader(System.in);
            out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
            Locale.setDefault(Locale.US);
            solve();
            out.close();
        } catch (Throwable e) {
            e.printStackTrace();
            System.exit(7);
        }
    }

    static int abs(int x) {
        return x < 0 ? -x : x;
    }

    static int max(int a, int b) {
        return a > b ? a : b;
    }

    static int min(int a, int b) {
        return a < b ? a : b;
    }

    static long abs(long x) {
        return x < 0 ? -x : x;
    }

    static long max(long a, long b) {
        return a > b ? a : b;
    }

    static long min(long a, long b) {
        return a < b ? a : b;
    }

    public static void main(String args[]) {
        new Thread(null, new Main(), "Main", 1 << 28).start();
    }

    static boolean OJ = System.getProperty("ONLINE_JUDGE") != null;

    public void console(Object... objects) {
        if (!OJ) {
            out.println(Arrays.deepToString(objects));
            out.flush();
        }
    }

    @SuppressWarnings({"Duplicates", "unused"})
    static class InputReader {

        private InputStream stream;
        private byte[] buf = new byte[2048];
        private int curChar;
        private int numChars;
        private SpaceCharFilter filter;

        public InputReader() {
            this.stream = System.in;
        }

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public InputReader(SpaceCharFilter filter) {
            this.stream = System.in;
            this.filter = filter;
        }

        public InputReader(InputStream stream, SpaceCharFilter filter) {
            this.stream = stream;
            this.filter = filter;
        }

        public int read() {
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

        public char nextChar() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            return (char) c;
        }

        public int nextDigit() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            return c - '0';
        }

        public int nextInt() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            boolean negative = false;
            if (c == '-') {
                negative = true;
                c = read();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return negative ? -res : res;
        }

        public int[] nextInts(int N) {
            int[] nums = new int[N];
            for (int i = 0; i < N; i++)
                nums[i] = nextInt();
            return nums;
        }

        public long[] nextLongs(int N) {
            long[] nums = new long[N];
            for (int i = 0; i < N; i++)
                nums[i] = nextLong();
            return nums;
        }

        public int nextUnsignedInt() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int res = 0;
            do {
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res;
        }

        public final long nextLong() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            boolean negative = false;
            if (c == '-') {
                negative = true;
                c = read();
            }
            long res = 0;
            do {
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return negative ? -res : res;
        }

        public final long nextUnsignedLong() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            long res = 0;
            do {
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res;
        }

        public double nextDouble() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            long sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            } while (!(c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1 || c == '.'));

            if (c != '.') {
                return res * sgn;
            }
            c = read();

            long aft = 0;
            int len = 1;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                aft *= 10;
                len *= 10;
                aft += c - '0';
                c = read();
            } while (!isSpaceChar(c));

            return res * sgn + aft / (1.0 * len);
        }

        public String nextLine() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isEndChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null)
                return filter.isSpaceChar(c);
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public boolean isEndChar(int c) {
            if (filter != null)
                return filter.isSpaceChar(c);
            return c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public String next() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public char[] nextChars() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));

            char[] chars = new char[res.length()];
            res.getChars(0, chars.length, chars, 0);
            return chars;
        }

        public int[][] nextIntMatrix(int rows, int cols) {
            int[][] matrix = new int[rows][cols];
            for (int i = 0; i < rows; i++)
                for (int j = 0; j < cols; j++)
                    matrix[i][j] = nextInt();
            return matrix;
        }

        public long[][] nextLongMatrix(int rows, int cols) {
            long[][] matrix = new long[rows][cols];
            for (int i = 0; i < rows; i++)
                for (int j = 0; j < cols; j++)
                    matrix[i][j] = nextLong();
            return matrix;
        }

        public char[][] nextCharMap(int rows, int cols) {
            char[][] matrix = new char[rows][cols];
            for (int i = 0; i < rows; i++)
                for (int j = 0; j < cols; j++)
                    matrix[i][j] = nextChar();
            return matrix;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
        }
    }
}