// AC: 202 ms

// Memory: 0 KB

// .

// T:O(n), S:O(n)

//

import java.util.ArrayDeque;

import java.util.Deque;

import java.util.Scanner;

public class Codeforces_0746B_Decoding {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

int n = sc.nextInt();

String s = sc.next();

StringBuilder ret = new StringBuilder();

Deque<Character> list = new ArrayDeque<>();

list.add(s.charAt(0));

for (int i = 1; i < n; i++) {

if (n % 2 == 0) {

if (i % 2 == 1) {

list.addLast(s.charAt(i));

} else {

list.addFirst(s.charAt(i));

}

} else {

if (i % 2 == 1) {

list.addFirst(s.charAt(i));

} else {

list.addLast(s.charAt(i));

}

}

}

for (char c : list) {

ret.append(c);

}

System.out.println(ret);

}

}