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<iostream>
#include<cstdio>
#include<vector>
#include<map>
#include<unordered_map>
#include<set>
#include<string>
#include<algorithm>
#include<math.h>
#include<numeric>
#include<iomanip>
#include<queue>
#include<functional>
#include<iso646.h>
#include<bitset>

using namespace std;

typedef vector<int> vi;
typedef pair<int, int> pii;
typedef long long ll;
typedef vector<long long> vll;
typedef pair<long long, long long> pll;

const ll INF = 1e10;
//const ll MOD = 1e9 + 7;
const ll MOD = 998244353;


int main(){
	string S;
	int w;
	cin >> S >> w;
	int len = S.length();
	int pos = 0;
	while (pos < len){
		cout << S[pos];
		pos += w;
	}
	cout << endl;
}