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>
#include <string.h>
int main(void)
{
  char s[1001];
  char S[1001];
  int w,j;
  int len;
  j=0;
 int a=1;
  scanf("%s",s);
  scanf("%d",&w);
  len=strlen(s);
  while (a==1) {
    for(int i=0;i<=1000;i++)
    {
      if(i%w==0)
      {

        S[j]=s[i];
        j++;
      }
      if(i>len){
        a=0;
      }

    }
  }

  printf("%s",S);
  return 0;
}