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 <bits/stdc++.h>
#define f first
#define s second
#define mp make_pair
#define pb push_back
#define lp(i,a,n) for(int i=a;i<=n;++i)
#define lpd(i,a,n) for(int i=a;i>=n;--i)
#define mem(a,b) memset(a,b,sizeof a)
#define all(v) v.begin(),v.end()
#define println(a) cout <<(a) <<endl
#define sz(x) ((int)(x).size())
#define readi(x) scanf("%d",&x)
#define read2i(x,y) scanf("%d%d",&x,&y)
#define read3i(x,y,z) scanf("%d%d%d",&x,&y,&z)
#define mod 1000000007
#define eps 1e-8
#define infi 1000000000
#define infll 1000000000000000000ll
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vll;
typedef set<int> si;
typedef map<int,int> mii;

const int N = 100002;
int n;
string s;

int main(){
    cin >>s >>n;
    for(int i = 0; i < sz(s); i += n) printf("%c", s[i]);
}

/*
freopen("input.txt","r",stdin);
freopen("output.txt","w",stdout);
*/