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.*;
import java.util.*;

public class Main {

	static final int mod = (int) 1e9 + 7;

	public static void main(String[] args) {
		FasterScanner s = new FasterScanner();
		PrintWriter out = new PrintWriter(System.out);
		int n=s.nextInt();
		long[] a=s.nextLongArray(n);
		for(int i=n-1;i>0;i--)
		{
			Arrays.sort(a);
			for(int j=0;j<n;j++){
				if(a[i]==a[j] && a[i]!=0 && j!=i)
					a[j]--;
			}
		}
		long sum=0;
		for(int i=0;i<n;i++){
			sum+=a[i];
		}
		System.out.println(sum);
		
		
		out.close();

	}

	static int[] primes;

	public static long ncr(int n, int r) {
		if (n < r)
			return 0;
		if (n == r)
			return 1;
		if (r == 0)
			return 1;
		if (r < 0)
			return 0;
		long ans = 1;
		for (int i = 0; i < primes.length; i++) {
			long power = count(n, primes[i]) - count(n - r, primes[i]) - count(r, primes[i]);
			ans *= pow(primes[i], power, mod);
			ans %= mod;
		}
		return ans;
	}

	public static long pow(long x, long n, int mod) {
		long res = 1;
		for (long p = x; n > 0; n >>= 1, p = (p * p) % mod) {
			if ((n & 1) != 0) {
				res = (int) (res * p % mod);
			}
		}
		return res;
	}

	public static long count(int n, int p) {
		long count = 0;
		long z = p;
		while (z <= n) {
			count += n / z;
			z *= p;
		}
		return count;

	}

	public static int[] generatePrimes(int n) {
		boolean[] prime = new boolean[n + 1];
		Arrays.fill(prime, 2, n + 1, true);
		for (int i = 2; i * i <= n; i++)
			if (prime[i])
				for (int j = i * i; j <= n; j += i)
					prime[j] = false;
		int[] primes = new int[n + 1];
		int cnt = 0;
		for (int i = 0; i < prime.length; i++)
			if (prime[i])
				primes[cnt++] = i;

		return Arrays.copyOf(primes, cnt);
	}

	public static class Pairxy implements Comparable<Pairxy> {
		int x;
		int y;
		long dist = 0;
		long dist2 = 0;

		Pairxy(int x, int y) {
			this.x = x;
			this.y = y;
			dist = x * 1l * x + y * 1l * y;
		}

		public int compareTo(Pairxy o) {
			if (this.dist != o.dist)
				return Long.compare(this.dist, o.dist);
			else
				return Integer.compare(this.x, o.x);

		}

	}

	public static class Pair implements Comparable<Pair> {
		long val;
		int ind;

		Pair(long v, int i) {
			val = v;
			ind = i;
		}

		public int compareTo(Pair o) {
			if (this.val != o.val)
				return Long.compare(this.val, o.val);
			return Integer.compare(this.ind, o.ind);
		}
	}

	public static long C(int n, int r) {
		long ans = 1;
		int x = 1;
		while (x <= r) {
			ans *= n;
			ans /= x;
			x++;
			n--;
		}
		return ans;
	}

	public static class DisjointSetsRank {

		int[] p;
		int[] rank;

		public DisjointSetsRank(int size) {
			p = new int[size];
			for (int i = 0; i < size; i++)
				p[i] = i;
			rank = new int[size];
		}

		public int root(int x) {
			return x == p[x] ? x : (p[x] = root(p[x]));
		}

		public int sameSet(int x, int y) {
			if (root(x) == root(y))
				return 1;
			return 0;

		}

		public void unite(int a, int b) {
			a = root(a);
			b = root(b);
			if (a == b)
				return;

			if (rank[a] < rank[b]) {
				p[a] = b;
			} else {
				p[b] = a;
				if (rank[a] == rank[b])
					++rank[a];
			}
		}

		public static void main(String[] args) {
			DisjointSetsRank ds = new DisjointSetsRank(10);
			System.out.println(false == (ds.root(0) == ds.root(9)));
			ds.unite(0, 9);
			System.out.println(true == (ds.root(0) == ds.root(9)));
		}
	}

	static int gcd(long m, long n) {
		long x;
		long y;
		while (m % n != 0) {
			x = n;
			y = m % n;
			m = x;
			n = y;
		}
		return (int) n;
	}

	public static class st {

		int n;
		long[] val;
		int[] index;

		void build(long[] t) { // build the tree
			this.n = t.length;
			val = new long[2 * n];
			index = new int[2 * n];

			for (int i = 0; i < n; i++) {
				val[n + i] = t[i];
				index[n + i] = i;
			}
			for (int i = n - 1; i >= 0; i--) {
				if (val[2 * i] > val[2 * i + 1]) {
					val[i] = val[2 * i];
					index[i] = index[2 * i];
				} else {
					val[i] = val[2 * i + 1];
					index[i] = index[2 * i + 1];
				}
			}
		}

		int query(int l, int r) { // sum on interval [l, r)
			int res = 0;
			long max = 0;
			for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
				if ((l & 1) != 0) {
					if (val[l] > max) {
						max = val[l];
						res = index[l];
					}
					l++;
				}
				if ((r & 1) != 0) {
					--r;
					if (val[r] > max) {
						max = val[r];
						res = index[r];
					}
				}
			}
			return res;
		}
	}

	public static class FasterScanner {
		private byte[] buf = new byte[1024];
		private int curChar;
		private int snumChars;

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

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

		public String nextString() {
			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 long nextLong() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int 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 (!isSpaceChar(c));
			return res * sgn;
		}

		public int nextInt() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				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 res * sgn;
		}

		public int[] nextIntArray(int n) {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextInt();
			}
			return arr;
		}

		public long[] nextLongArray(int n) {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		}

		private boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}
	}
}