Artem has an array of n positive integers. Artem decided to play with it. The game consists of n moves. Each move goes like this. Artem chooses some element of the array and removes it. For that, he gets min(a, b) points, where a and b are numbers that were adjacent with the removed number. If the number doesn't have an adjacent number to the left or right, Artem doesn't get any points. 

After the element is removed, the two parts of the array glue together resulting in the new array that Artem continues playing with. Borya wondered what maximum total number of points Artem can get as he plays this game.

Input

The first line contains a single integer n (1 ≤ n ≤ 5·105) — the number of elements in the array. The next line contains n integers ai (1 ≤ ai ≤ 106) — the values of the array elements.

Output

In a single line print a single integer — the maximum number of points Artem can get.

Examples

Input

5
3 1 5 2 6


Output

11


Input

5
1 2 3 4 5


Output

6


Input

5
1 100 101 100 1


Output

102
import java.io.*;
import java.util.*;

public class p83
{
	public static void main(String[] args)
	{
		FastScanner in = new FastScanner();
		int n = in.nextInt();
		int data[] = new int[n];
		TreeSet<Pair> mins = new TreeSet<Pair>(new Comparator<Pair>(){
			@Override
			public int compare(Pair a, Pair b) {
				if(a.v != b.v)
					return Integer.compare(a.v, b.v);
				return Integer.compare(a.i, b.i);
			}
		});
		TreeSet<Pair> ids = new TreeSet<Pair>(new Comparator<Pair>(){
			@Override
			public int compare(Pair a, Pair b) {
				if(a.i != b.i)
					return Integer.compare(a.i, b.i);
				return Integer.compare(a.v, b.v);
			}
		});
		
		for(int i = 0; i < n; i++)
		{
			data[i] = in.nextInt();
			Pair p = new Pair(data[i], i);
			ids.add(p);
			mins.add(p);
		}
		
		long ans = 0;
		int lo = 0;
		int hi = n-1;
		for(int i = 0; i < n-2; i++)
		{
			Pair min = mins.pollFirst();
			if(min.i == lo)
			{
				lo = ids.higher(min).i;
				ans += min.v;
				continue;
			}
			if(min.i == hi)
			{
				hi = ids.lower(min).i;
				ans += min.v;
				continue;
			}
			
			ids.remove(min);
			Pair left = ids.floor(min);
			Pair right = ids.ceiling(min);
			
			ans += Math.min(data[left.i], data[right.i]);
		}
		
		System.out.println(ans);
	}
	
	public static class Pair
	{
		int v, i;
		
		public Pair(int vv, int ii)
		{
			v = vv;
			i = ii;
		}
	}
	
	public static class FastScanner
	{
		BufferedReader br;
		StringTokenizer st;

		public FastScanner(String s)
		{
			try {
				br = new BufferedReader(new FileReader(s));
			} catch (FileNotFoundException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}

		public FastScanner()
		{
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String nextToken()
		{
			while (st == null || !st.hasMoreElements())
			{
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt()
		{
			return Integer.parseInt(nextToken());
		}

		long nextLong()
		{
			return Long.parseLong(nextToken());
		}

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