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: Runtime Error)

#include<stdio.h>

int main()
{
	int w,i,j;
	char S[2000];
	scanf("%s",S);
	scanf("%d",&w);
	for(i=0; S[i] != '\0'; i++){
	}
	if(i%j == 0){
		for(j=0; j<i/w; j++){
			printf("%c",S[w*j]);
		}
	}
	else
		for(j=0; j<=i/w; j++){
			printf("%c",S[w*j]);
		}
	
	return 0;
}