#626. Sum at odd positions
Find the sum of the elements at positions 1, 3, 5, ... (counting from 1).
### Input
The first line has n, the second line has n integers separated by spaces.
### Output
A number.
Examples
Input
4 36 -25 27 -26
Output
63
Input
5 7 -7 -30 -24 42
Output
19
💡 You can solve it with Python, JavaScript or blocks. Read the input line by line with input(). Don't print a question (like input("Number: ")). Print exactly what the output asks for, nothing more.