output_description: Print the desired string in one line.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      S
      w
attempt: #include <map>
  #include <set>
  #include <list>
  #include <cmath>
  #include <queue>
  #include <stack>
  #include <cstdio>
  #include <string>
  #include <vector>
  #include <complex>
  #include <cstdlib>
  #include <cstring>
  #include <numeric>
  #include <sstream>
  #include <iostream>
  #include <algorithm>
  #include <functional>
  #include <unordered_map>
  #include <random>
  #include <iomanip>
    
  #define mp       make_pair
  #define pb       push_back
  #define all(x)   (x).begin(),(x).end()
  #define rep(i,n) for(int i=0;i<(n);i++)
    
  using namespace std;
    
  typedef    long long          ll;
  typedef    unsigned long long ull;
  typedef    vector<bool>       vb;
  typedef    vector<int>        vi;
  typedef    vector<vb>         vvb;
  typedef    vector<vi>         vvi;
  typedef    pair<int,int>      pii;
    
  const int INF=1<<29;
  const double EPS=1e-9;
    
  const int dx[]={1,0,-1,0,1,1,-1,-1},dy[]={0,-1,0,1,1,-1,-1,1};
  
  int main() {
    string s;
    cin >> s;
    int N;
    cin >> N;
    for(int i = 0; i < s.size(); i += N) {
      cout << s[i];
    }
    cout << endl;
    return 0;
  }
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"}]