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:
// Long Contest 1, Problem P
import java.nio.charset.Charset;
import java.lang.StringBuilder;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;

public class Main {
	public static void main(String[] args) {
		Charset charset = Charset.forName("ascii");
	    FastIO rd = new FastIO(System.in, System.out, charset);
	    
	    int n = rd.readInt();
	    String word = rd.readString();
	    String res = "";
	    
	    if(n%2 == 0) {
	    	for(int i=0; i < n; i++) {
	    		char ch = word.charAt(i);
	    		if(i%2 == 0) {
	    			res = ch+res;
	    		}
	    		else {
	    			res = res+ch;
	    		}
	    	}
	    }
	    else {
	    	for(int i=0; i < n; i++) {
	    		char ch = word.charAt(i);
	    		if(i%2 == 0) {
	    			res = res+ch;
	    		}
	    		else {
	    			res = ch+res;
	    		}
	    	}
	    }
	    
	    System.out.println(res);
	}
}


class FastIO {
    public final StringBuilder cache = new StringBuilder(1 << 20);
    private final InputStream is;
    private final OutputStream os;
    private final Charset charset;
    private StringBuilder defaultStringBuf = new StringBuilder(1 << 8);
    private byte[] buf = new byte[1 << 13];
    private int bufLen;
    private int bufOffset;
    private int next;
    
    public FastIO(InputStream is, OutputStream os, Charset charset) {
        this.is = is;
        this.os = os;
        this.charset = charset;
    }
    
    public FastIO(InputStream is, OutputStream os) {
        this(is, os, Charset.forName("ascii"));
    }
    
    private int read() {
        while (bufLen == bufOffset) {
            bufOffset = 0;
            try {
                bufLen = is.read(buf);
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
            if (bufLen == -1) {
                return -1;
            }
        }
        return buf[bufOffset++];
    }
    
    public void skipBlank() {
        while (next >= 0 && next <= 32) {
            next = read();
        }
    }
    
    public int readInt() {
        int sign = 1;
        
        skipBlank();
        if (next == '+' || next == '-') {
            sign = next == '+' ? 1 : -1;
            next = read();
        }
        
        int val = 0;
        if (sign == 1) {
            while (next >= '0' && next <= '9') {
                val = val * 10 + next - '0';
                next = read();
            }
        } else {
            while (next >= '0' && next <= '9') {
                val = val * 10 - next + '0';
                next = read();
            }
        }
        
        return val;
    }
    
    public long readLong() {
        int sign = 1;
        
        skipBlank();
        if (next == '+' || next == '-') {
            sign = next == '+' ? 1 : -1;
            next = read();
        }
        
        long val = 0;
        if (sign == 1) {
            while (next >= '0' && next <= '9') {
                val = val * 10 + next - '0';
                next = read();
            }
        } else {
            while (next >= '0' && next <= '9') {
                val = val * 10 - next + '0';
                next = read();
            }
        }
        
        return val;
    }
    
    public double readDouble() {
        boolean sign = true;
        skipBlank();
        if (next == '+' || next == '-') {
            sign = next == '+';
            next = read();
        }
        
        long val = 0;
        while (next >= '0' && next <= '9') {
            val = val * 10 + next - '0';
            next = read();
        }
        if (next != '.') {
            return sign ? val : -val;
        }
        next = read();
        long radix = 1;
        long point = 0;
        while (next >= '0' && next <= '9') {
            point = point * 10 + next - '0';
            radix = radix * 10;
            next = read();
        }
        double result = val + (double) point / radix;
        return sign ? result : -result;
    }
    
    public String readString(StringBuilder builder) {
        skipBlank();
        
        while (next > 32) {
            builder.append((char) next);
            next = read();
        }
        
        return builder.toString();
    }
    
    public String readString() {
        defaultStringBuf.setLength(0);
        return readString(defaultStringBuf);
    }
    
    public String readLine() {
        skipBlank();
        String s="";
        int offset = 0;
        while (next != -1 && next != '\n') {
            s += (char) next;
            next = read();
        }
        return s;
    }
    
    public int readString(char[] data, int offset) {
        skipBlank();
        
        int originalOffset = offset;
        while (next > 32) {
            data[offset++] = (char) next;
            next = read();
        }
        
        return offset - originalOffset;
    }
    
    public int readString(byte[] data, int offset) {
        skipBlank();
        
        int originalOffset = offset;
        while (next > 32) {
            data[offset++] = (byte) next;
            next = read();
        }
        
        return offset - originalOffset;
    }
    
    public char readChar() {
        skipBlank();
        char c = (char) next;
        next = read();
        return c;
    }
    
    public void flush() {
        try {
            os.write(cache.toString().getBytes(charset));
            os.flush();
            cache.setLength(0);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
    
    public boolean hasMore() {
        skipBlank();
        return next != -1;
    }
}