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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<algorithm>
#include<climits>
#include<cmath>
#include<iomanip>
#include<iostream>
#include<map>
#include<numeric>
#include<queue>
#include<set>
#include<stack>
#include<utility>
#include<vector>

#define lint long long
#define VI vector<int>
#define VL vector<lint>
#define VC vector<char>
#define VVI vector<vector<int>>
#define rep(i, n) for(int i = 0 ; i < n ; i++)
#define SORT(c) sort((c).begin(), (c).end())
#define SORT_INV(c) sort((c.begin(), c.end(), greater<int>())
#define IINF INT_MAX
#define LLINF LLONG_MAX

using namespace std;

int main(){
    string s;
    cin >> s;
    int w;
    cin >> w;
    for(int i = 0 ; i < s.size() ; i += w){
        cout << s[i];
    }
    cout << endl;
    return 0;
}