Problem Statement

There was a contest with N problems. The $i-th (1\leq i\leq N) problem was worth A_i$ points.
Snuke took part in this contest and solved M problems: the $B_1-th, B_2-th, \ldots$, and B_M-th ones.
Find his total score.
Here, the total score is defined as the sum of the points for the problems he solved.

Input

The input is given from Standard Input in the following format:
N M
$A_1 A_2 \dots A_N$
$B_1 B_2 \dots B_M$

Output

Print the answer as an integer.

Constraints

• $1\leq M \leq N \leq 100$
• $1\leq A_i \leq 100$
• $1\leq B_1 < B_2 < \ldots < B_M \leq N$
• All values in the input are integers.

Sample Input 1

3 2
10 20 30
1 3

Sample Output 1

40

Snuke solved the 1-st and 3-rd problems,
which are worth 10 and 30 points, respectively. Thus, the total score is 10+30=40 points.

Sample Input 2

4 1
1 1 1 100
4

Sample Output 2

100

Sample Input 3

8 4
22 75 26 45 72 81 47 29
4 6 7 8

Sample Output 3

202

见题面 Input 部分

见题面 Output 部分