Problem:
Score : 300 points

Problem Statement

There is an integer sequence A of length N whose values are unknown.

Given is an integer sequence B of length N-1 which is known to satisfy the following:

B_i \geq \max(A_i, A_{i+1})

Find the maximum possible sum of the elements of A.

Constraints

All values in input are integers.

2 \leq N \leq 100

0 \leq B_i \leq 10^5

Input

Input is given from Standard Input in the following format:

N
B_1 B_2 ... B_{N-1}

Output

Print the maximum possible sum of the elements of A.

Sample Input 1

3
2 5

Sample Output 1

9

A can be, for example, ( 2 , 1 , 5 ), ( -1 , -2 , -3 ), or ( 2 , 2 , 5 ). Among those candidates, A = ( 2 , 2 , 5 ) has the maximum possible sum.

Sample Input 2

2
3

Sample Output 2

6

Sample Input 3

6
0 153 10 10 23

Sample Output 3

53

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {

	public static void main(String[] args) throws Exception {
		// TODO 自動生成されたメソッド・スタブ
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		String W = in.readLine();
		int N = Integer.parseInt(W);

		W = in.readLine();
		String[] Ws = W.split(" ");
		int[] B = new int[Ws.length];
		for(int i=0;i<Ws.length;i++){
			B[i]=Integer.parseInt(Ws[i]);
		}

		int[] A = new int[N];
		A[0]=B[0];
		for(int i=1;i<N-1;i++){
			A[i] = Math.min(B[i-1], B[i]);
		}

		A[N-1]=B[N-2];

		long ans =0;
		for(int i=0;i<N;i++){
			ans+=A[i];
			System.out.print(A[i]+" ");
		}

		System.out.println(ans);
	}
}