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 C (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
int str_length(const char s[])
{
	int len = 0;
	while (s[len])len++;
	return len;
}
int main()
{
	char s[1001];
	int w,i,n;
	scanf("%s", s);
	scanf("%d", &w);
	n = str_length(s);
	for (i = 0;i < n;i+=w)
		printf("%c", s[i]);

	return 0;
}