Problem: Polycarp loves ciphers. He has invented his own cipher called repeating.

Repeating cipher is used for strings. To encrypt the string s=s_{1}s_{2} ... s_{m} (1 ≤ m ≤ 10), Polycarp uses the following algorithm:

  * he writes down s_1 ones, 
  * he writes down s_2 twice, 
  * he writes down s_3 three times, 
  * ... 
  * he writes down s_m m times. 



For example, if s="bab" the process is: "b" → "baa" → "baabbb". So the encrypted s="bab" is "baabbb".

Given string t — the result of encryption of some string s. Your task is to decrypt it, i. e. find the string s.

Input

The first line contains integer n (1 ≤ n ≤ 55) — the length of the encrypted string. The second line of the input contains t — the result of encryption of some string s. It contains only lowercase Latin letters. The length of t is exactly n.

It is guaranteed that the answer to the test exists.

Output

Print such string s that after encryption it equals t.

Examples

Input


6
baabbb


Output


bab

Input


10
ooopppssss


Output


oops

Input


1
z


Output


z

Solution (in JAVA):

Solution:
/* package codechef; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.Arrays;
import java.math.BigInteger;
 
/* Name of the class has to be "Main" only if the class is public. */
public class Main
{
     public static void main (String[] args) throws java.lang.Exception
     {
     	Scanner in =new Scanner(System.in);
		int t=1,i,j,l,n,m,k=0,p=0,h=0;
		String s="",st="";
		long x=0;
		for(i=0;i<t;i++)
		{
		     s=in.next();
		     n=s.length();
		     char c[]=s.toCharArray();
		     if(n%2==0)
		     {
		          st+=c[n/2-1];
		          for(j=n/2,k=n/2-2;j<n-1;j++,k--)
		          {
		               st+=c[j];
		               st+=c[k];
		          }
		          st+=c[n-1];
		     }
		     else
		     {
		          st+=c[n/2];
		          for(j=n/2+1,k=n/2-1;j<n;j++,k--)
		          {
		               st+=c[j];
		               st+=c[k];
		          }
		     }
		     System.out.println(st);
		}
	}
}