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 Go (1.6) (judge verdict: Accepted)

package main

import "fmt"

var s string
var w int

func main() {
	fmt.Scan(&s, &w)
	ans := []string{}
	for i := 0; i < len([]rune(s)); i += w {
		ans = append(ans, string([]rune(s)[i]))
	}
	for _, a := range ans {
		fmt.Print(a)
	}
	fmt.Println()
}