Problem:
Score : 200 points

Problem Statement

You are given a string S consisting of lowercase English letters.
We will write down this string, starting a new line after every w letters. Print the string obtained by concatenating the letters at the beginnings of these lines from top to bottom.

Constraints

1 \leq w \leq |S| \leq 1000

S consists of lowercase English letters.

w is an integer.

Input

Input is given from Standard Input in the following format:

S
w

Output

Print the desired string in one line.

Sample Input 1

abcdefgh
3

Sample Output 1

adg

When we write down abcdefgh, starting a new line after every three letters, we get the following:

abc

def

gh

Concatenating the letters at the beginnings of these lines, we obtain adg.

Sample Input 2

lllll
1

Sample Output 2

lllll

Sample Input 3

souuundhound
2

Sample Output 3

suudon

Solution in JavaScript (node.js v5.12) (judge verdict: Accepted)

"use strict";
    
const main = arg => {
    arg = arg.trim().split("\n");
    const S = arg[0].split("");
    const W = parseInt(arg[1]);
    
    let answer = [];
    
    for(let i in S) {
        if(i % W === 0) {
            answer.push(S[i]);
        }
    }
    
    console.log(answer.join(""));
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));