import java.util.*;
class main{
    public static void main(String args[]){
        Scanner sc=new Scanner(System.in);
        String a=sc.nextLine();
        if(a.length<n){
            System.out.println("Invalid input");
            return;
        }
        int n=sc.nextInt();
        char [][]arr=new char[n][a.length()];
        int r=0;
        int c=0;
        int current=0;
     
        while(current<a.length())
        {
            while(r<n && current<a.length())
            {
                arr[r++][c]=a.charAt(current++);
            }
                r=Math.max(0,n-2);
            while(r>0 && current<a.length())
            {
                arr[r--][++c]=a.charAt(current++);
            }
            c++;
            }
             String ans=" ";
            for(int i=0;i<n;i++){
                for(int j=0;j<a.length();j++){
                    if(Character.isLetter(arr[i][j])){
                        ans=ans+arr[i][j];
                    }
              
                }
            }
             System.out.println(ans);
        }
    }