output_description: Print the desired string in one line.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      S
      w
attempt: #define _CRT_SECURE_NO_WARNINGS
  #define _USE_MATH_DEFINES
  #include <stdio.h>
  #include <string.h>
  #include <stdlib.h>
  #include <math.h>
  #include <iostream>
  #include <vector>
  #include <algorithm>
  #include <string>
  #include <functional>
  #include <stack>
  #include <queue>
  #include <cstdio>
  #include <cstdlib>
  #include <cstring>
  #include <list>
  #include <set>
  using namespace std;
  typedef long long ll;
  
  
  int main(int argc, char *args[]) {
  	string s;
  	int w;
  	
  	int i = 0;
  	int counter = 1;
  	cin >> s >> w;
  	
  	
  	while (counter <= s.size()) {
  		cout << s[0 + i * w];
  		i++;
  		counter = counter + w;
  	}
  	cout << endl;
  }
  
problem_description: 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.
samples: [{"input": "abcdefgh\n    3", "output": "adg\n    \n\nWhen we write down `abcdefgh`, starting a new line after every three letters,\nwe get the following:\n\nabc  \ndef  \ngh\n\nConcatenating the letters at the beginnings of these lines, we obtain `adg`.\n\n* * *"}, {"input": "lllll\n    1", "output": "lllll\n    \n\n* * *"}, {"input": "souuundhound\n    2", "output": "suudon"}]