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.util.Scanner;
import java.io.*;
import java.util.*;
import java.math.*;
import java.lang.*;
import static java.lang.Math.*;
 
public class TestClass //implements Runnable
{
	int x,y,cost;
	public TestClass(int x,int y,int cost)
	{
		this.x=x;
		this.y=y;
		this.cost=cost;
	}
	
	public static void main(String args[]) throws Exception
	{/*
		new Thread(null, new TestClass(),"TESTCLASS",1<<18).start();
	}
	public void run()
	{*/
		//Scanner scan=new Scanner(System.in);
		InputReader hb=new InputReader(System.in);
		PrintWriter w=new PrintWriter(System.out);
		
		int n=hb.nextInt();
		HashSet<Integer> set=new HashSet<Integer>();
		long ans=0;
		for(int i=0;i<n;i++)
		{
			int x=hb.nextInt();
			if(set.add(x))
				ans+=x;
			else
			{
				int j;
				for(j=x-1;j>0;j--)
				{
					if(set.add(j))
					{
						ans+=j;
						break;
					}
				}
			}
			//w.println(ans);
		}
		w.print(ans);
		w.close();
	}
	
	
	private void shuffle(int[] arr)
	{
		Random ran = new Random();
		for (int i = 0; i < arr.length; i++) {
			int i1 = ran.nextInt(arr.length);
			int i2 = ran.nextInt(arr.length);

			int temp = arr[i1];
			arr[i1] = arr[i2];
			arr[i2] = temp;
		}
	}
	
	static class DSU
	{
		int parent[];
		int sizeParent[];
		DSU(int n)
		{
			parent=new int[n];
			sizeParent=new int[n];
			Arrays.fill(sizeParent,1);
			for(int i=0;i<n;i++)
				parent[i]=i;
		}
		
		int find(int x)
		{
			if(x!=parent[x])
				parent[x]=find(parent[x]);
			return parent[x];
		}
		
		void union(int x,int y)
		{
			x=find(x);
			y=find(y);
			if(sizeParent[x]>=sizeParent[y])
			{
				if(x!=y)
					sizeParent[x]+=sizeParent[y];
				parent[y]=x;
			}
			else
			{
				if(x!=y)
					sizeParent[y]+=sizeParent[x];
				parent[x]=y;
			}
		}
	}
	
	static class InputReader
	{
		private InputStream stream;
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;
		private SpaceCharFilter filter;
		
		public InputReader(InputStream stream)
		{
			this.stream = stream;
		}
		
		public int read()
		{
			if (numChars==-1) 
				throw new InputMismatchException();
			
			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 String nextLine()
		{
			BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
			String str = "";
			try
			{
				str = br.readLine();
			}
			catch (IOException e)
			{
				e.printStackTrace();
			}
			return str;
		}
		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 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 double nextDouble() 
		{
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') 
			{
				sgn = -1;
				c = read();
			}
			double res = 0;
			while (!isSpaceChar(c) && c != '.') 
			{
				if (c == 'e' || c == 'E')
					return res * Math.pow(10, nextInt());
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			}
			if (c == '.') 
			{
				c = read();
				double m = 1;
				while (!isSpaceChar(c)) 
				{
					if (c == 'e' || c == 'E')
						return res * Math.pow(10, nextInt());
					if (c < '0' || c > '9')
						throw new InputMismatchException();
					m /= 10;
					res += (c - '0') * m;
					c = read();
				}
			}
			return res * sgn;
		}
		
		public String readString() 
		{
			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 boolean isSpaceChar(int c) 
		{
			if (filter != null)
				return filter.isSpaceChar(c);
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}
	 
		public String next() 
		{
			return readString();
		}
		
		public interface SpaceCharFilter 
		{
			public boolean isSpaceChar(int ch);
		}
	}
 
	static class Pair implements Comparable<Pair>
	{
		int a;
		int b;
		String str;
		public Pair(int a,int b)
		{
			this.a=a;
			this.b=b;
			str=min(a,b)+" "+max(a,b);
		}
 
		public int compareTo(Pair pair)
		{
			if(Integer.compare(a,pair.a)==0)
				return Integer.compare(b,pair.b);
 
			return Integer.compare(a,pair.a);
		}
	}
 
	
}