Problem Statement

You are given an integer sequence of length $N$: $A=(A_1,A_2,\dots,A_N)$. Here, $N$ is even. Find the sum of the latter half of $A$, that is, the sum of $A_{(N/2)+1},A_{(N/2)+2},\dots,A_{N}$.

Constraints

• All input values are integers.
• $N$ is an even number satisfying $2 \le N \le 100$.
• $1 \le A_i \le 100$

Input

The input is given from Standard Input in the following format:

• $N$
• $A_1$ $A_2$ $\dots$ $A_N$

Output

Output the answer.

8
1 3 7 8 4 2 5 6

17

The length of the sequence $A$ is $N=8$, and you should find the sum of $A_5,A_6,A_7,A_8$. Since $A_5+A_6+A_7+A_8 = 4+2+5+6=17$, output $17$.

2
1 100

100

10
31 41 59 26 53 58 97 93 23 84

355

• Source: AtCoder ABC 473 A