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)

// Nihesh Anderson - knandy

#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 

using namespace __gnu_pbds;
using namespace std;

typedef long long ll;
typedef tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
ll MOD=1000000007;

#define fast_cin() ios_base::sync_with_stdio(false)
#define pb push_back
#define gcd(a,b) __gcd((a),(b))
#define lcm(a,b) ((a)*(b))/gcd((a),(b))
#define debug1(x) cerr << x << endl;
#define debug2(x,y) cerr << x << " " << y << endl;
#define debug3(x,y,z) cerr << x << " " << y << " " << z << endl;
#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define FORR(i, a, b) for (int i=a; i>=(b); i--)
ll INF = 2000000000000000001;
double EPS = 1e-9;
ll nextInt(){ll inp; cin>>inp; return inp;}
string nextStr(){string inp; cin>>inp; return inp;}
double nextDouble(){double inp; cin>>inp; return inp;}
ll power(ll a, ll n, ll md){if(n==0){return 1;}else{int res=power(a,n/2,md);res=(res*res)%md;if(n%2!=0){res=(res*a)%md;}return res;}}
random_device rndm;
mt19937 grndm(rndm());
void mix(int* a, int* b){shuffle(a,b,grndm);}

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