Problem: Polycarp is mad about coding, that is why he writes Sveta encoded messages. He calls the median letter in a word the letter which is in the middle of the word. If the word's length is even, the median letter is the left of the two middle letters. In the following examples, the median letter is highlighted: contest, info. If the word consists of single letter, then according to above definition this letter is the median letter. 

Polycarp encodes each word in the following way: he writes down the median letter of the word, then deletes it and repeats the process until there are no letters left. For example, he encodes the word volga as logva.

You are given an encoding s of some word, your task is to decode it. 

Input

The first line contains a positive integer n (1 ≤ n ≤ 2000) — the length of the encoded word.

The second line contains the string s of length n consisting of lowercase English letters — the encoding.

Output

Print the word that Polycarp encoded.

Examples

Input

5
logva


Output

volga


Input

2
no


Output

no


Input

4
abba


Output

baba

Note

In the first example Polycarp encoded the word volga. At first, he wrote down the letter l from the position 3, after that his word looked like voga. After that Polycarp wrote down the letter o from the position 2, his word became vga. Then Polycarp wrote down the letter g which was at the second position, the word became va. Then he wrote down the letter v, then the letter a. Thus, the encoding looked like logva.

In the second example Polycarp encoded the word no. He wrote down the letter n, the word became o, and he wrote down the letter o. Thus, in this example, the word and its encoding are the same.

In the third example Polycarp encoded the word baba. At first, he wrote down the letter a, which was at the position 2, after that the word looked like bba. Then he wrote down the letter b, which was at the position 2, his word looked like ba. After that he wrote down the letter b, which was at the position 1, the word looked like a, and he wrote down that letter a. Thus, the encoding is abba.

Solution (in JAVA):

Solution:
import javafx.util.Pair;

import java.io.*;
import java.util.*;
public class test {
    long max = 0;
    long t[];
    boolean visited[];
    int sign[]={1,0,-1,0,0,1,0,-1};
    ArrayList<Integer> queue = new ArrayList<>();

    public static void main(String args[]) throws IOException {
        test obj = new test();
        obj.start();
    }

    void start() throws IOException {
        Scanner sc=new Scanner(System.in);
        PrintStream out = System.out;
        int n=sc.nextInt();
        String s=sc.next();
        String t1="";
        String t2="";
        String a="";
        int start=0;
        if(n%2==1) {
            a = s.charAt(0) + "";
            start=1;
        }
        for(int i=0;i<n/2;i++)
        {
            t1=s.charAt(start++)+t1;
            t2=t2+s.charAt(start++);
        }
        out.println(t1+a+t2);
    }


    //<---------------------------------------------------------------------------------------------------------------->//


    //printing 2-d array
    private void println(char[][] a,int n,int m) {
        for(int i=0;i<n;i++)
        {
            for(int j=0;j<m;j++)
                System.out.print(a[i][j]);
            System.out.println();
        }

    }


    //modified dfs for chessboard, matrix
    void dfs(char a[][],int i,int j,char t,int n,int m)
    {
        //visited[i]=true;
        a[i][j]=t;
        if(t=='B')
            t='W';
        else
            t='B';
        for (int c= 0; c < 4; c++) {

            int temp=i+sign[2*c];
            int temp2=j+sign[2*c+1];
            if(temp>=0&&temp<n&&temp2>=0&&temp2<m) {
                if(a[temp][temp2]=='.'&&a[temp][temp2]!='-')
                    dfs(a,temp,temp2,t,n,m);
            }
        }
    }


     //constructing segment tree
    private void constructseg(long[] seg, long[] input, int p, int q, int pos) {
        if(p==q)
        {
            seg[pos]=input[p];
            return;
        }
        int mid=(q+p)/2;
        constructseg(seg,input,p,mid,2*pos+1);
        constructseg(seg,input,mid+1,q,2*pos+2);
        seg[pos]=seg[2*pos+1]+seg[2*pos+2];
    }


    //traversing through a arrayList graph
    void dfs(ArrayList<Integer> node[],int i,int count,int cat[],int k)
    {
        visited[i]=true;
        if(cat[i]==1) {
            count++;
        }
        else
            count=0;
        if(count>k) {
            return;
        }
        if(node[i].size()==1&&i!=0) {
            max += 1;
        }
        for (int j = 0; j < node[i].size(); j++) {
            if(!visited[node[i].get(j)])
                dfs(node, node[i].get(j), count, cat, k);
        }

    }


    //printing arraylist array
    void println(ArrayList<Integer> a[])
    {
          for (ArrayList<Integer> b:a
               ) {
              System.out.println(b.toString());
          }
    }

    //sorting 2 array based on a, Complexity is O(n^2)
    void sort(int a[],int b[],int n)
    {
        for(int i=1;i<n;i++)
        {
            int index=i;
            for(int j=i-1;j>=0;j--)
            {
              //  println(a);
                if(a[index]<a[j])
                {
                    int temp=a[index];
                    int temp2=b[index];
                    a[index]=a[j];
                    b[index]=b[j];
                    a[j]=temp;
                    b[j]=temp2;
                    index=j;

                }
                else
                    break;
            }
        }

    }
     // to create and initialize Integer array
    private int[] intArray(int a, Scanner sc) {
        int temp[]=new int[a];
        for(int i=0;i<a;i++) {
            temp[i]=sc.nextInt();
        }
        return temp;
    }
    // to create and initialize Long Array
    private long[] longArray(int a, Scanner sc) {
        long temp[]=new long[a];
        for(int i=0;i<a;i++) {
            temp[i]=sc.nextLong();
        }
        return temp;
    }

    // displaying Map contents key--value
    public static void printMap(Map mp) {
        Iterator it = mp.entrySet().iterator();
        while (it.hasNext()) {
            Map.Entry pair = (Map.Entry)it.next();
            System.out.println(pair.getKey() + " = " + pair.getValue());
            it.remove(); // avoids a ConcurrentModificationException
        }
    }


    // Return arrayList of minimum factor of number
    // 24= 2*2*2*3;
    private ArrayList<Integer> minFactor(int a) {
        ArrayList<Integer> obj=new ArrayList<>();
        for(int i=2;i<=a;i++)
        {
            while(a!=0&&a%i==0)
            {
                obj.add(i);
                a/=i;
            }
        }
        return obj;
    }


    // check whether the number is prime or not
    public static boolean isPrimeNumber(int i) {
        int factors = 0;
        int j = 1;

        while(j <= i)
        {
            if(i % j == 0)
            {
                factors++;
            }
            j++;
        }
        return (factors == 2);
    }

    // creating and initializing arrayList
    private void initArrayList(ArrayList<Integer>[] tempa) {
        for(int i=0;i<tempa.length;i++)
            tempa[i]=new ArrayList<>();
    }

    // return factorial contents as ArrayList
    private ArrayList<Integer> factdigit(int i)
    {
        ArrayList<Integer> temp=new ArrayList<>();
        for(int j=i;j>1;j--)
        {
            temp.add(j);
        }
        return temp;
    }

    //printing Integer array
    private  void println(int a[])
    {
        for(int i=0;i<a.length;i++)
            System.out.print(a[i]+" ");
    }
}


class Reader {
    final private int BUFFER_SIZE = 1 << 16;
    private DataInputStream din;
    private byte[] buffer;
    private int bufferPointer, bytesRead;

    public Reader() {
        din = new DataInputStream(System.in);
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    public Reader(String file_name) throws IOException {
        din = new DataInputStream(new FileInputStream(file_name));
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    public String readLine() throws IOException {
        byte[] buf = new byte[300]; // line length
        int cnt = 0, c;
        while ((c = read()) != -1) {
            if (c == '\n')
                break;
            buf[cnt++] = (byte) c;
        }
        return new String(buf, 0, cnt);
    }

    public int nextInt() throws IOException {
        int ret = 0;
        byte c = read();
        while (c <= ' ')
            c = read();
        boolean neg = (c == '-');
        if (neg)
            c = read();
        do {
            ret = ret * 10 + c - '0';
        } while ((c = read()) >= '0' && c <= '9');

        if (neg)
            return -ret;
        return ret;
    }

    public long nextLong() throws IOException {
        long ret = 0;
        byte c = read();
        while (c <= ' ')
            c = read();
        boolean neg = (c == '-');
        if (neg)
            c = read();
        do {
            ret = ret * 10 + c - '0';
        }
        while ((c = read()) >= '0' && c <= '9');
        if (neg)
            return -ret;
        return ret;
    }

    public double nextDouble() throws IOException {
        double ret = 0, div = 1;
        byte c = read();
        while (c <= ' ')
            c = read();
        boolean neg = (c == '-');
        if (neg)
            c = read();

        do {
            ret = ret * 10 + c - '0';
        }
        while ((c = read()) >= '0' && c <= '9');

        if (c == '.') {
            while ((c = read()) >= '0' && c <= '9') {
                ret += (c - '0') / (div *= 10);
            }
        }

        if (neg)
            return -ret;
        return ret;
    }

    private void fillBuffer() throws IOException {
        bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
        if (bytesRead == -1)
            buffer[0] = -1;
    }

    private byte read() throws IOException {
        if (bufferPointer == bytesRead)
            fillBuffer();
        return buffer[bufferPointer++];
    }

    public void close() throws IOException {
        if (din == null)
            return;
        din.close();
    }
}