The number of inhabitants living in each house of the street is known. Houses are numbered in a row, starting from 1. Houses with odd numbers are located on one side of the street, with even ones on the other. Determine how many people live on the even side of the street.
Input
The first line contains the number
N (1<=N<=20) - the number of elements of a one-dimensional array. The second line contains
N integers (each number is not over 1000).
Imprint
Print a single number - the number of people who live on the even side of the street.
Examples
| # |
Input |
Output |
| 1 |
6
202 103 484 287 282 238
|
628 |