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.

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.

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.

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