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 PYTHON3):

Solution:
# sys.setrecursionlimit(300000)
import sys
def main():
    pass
def binary(n):
    # decimal to binary
    return (bin(n).replace("0b", ""))
def decimal(s):
    # binary to decimal
    return (int(s, 2))
def pow2(n):
    # power of a number base 2
    p = 0
    while n > 1:
        n //= 2
        p += 1
    return (p)
def isPrime(n):
    # if  number is prime in √n time
    if (n == 1):
        return (False)
    else:
        root = int(n ** 0.5)
        root += 1
        for i in range(2, root):
            if (n % i == 0):
                return (False)
        return (True)
def lts(l):
    # list to string ,no spaces
    s = ''.join(map(str, l))
    return s
def stl(s):
    # for each character in string to list with no spaces -->
    l = list(s)
    # for space in string  -->
    # l=list(s.split(" "))
    return l
# Returns list of numbers with a particular sum
def sq(a, target, arr=[]):
    s = sum(arr)
    if (s == target):
        return arr
    if (s >= target):
        return
    for i in range(len(a)):
        n = a[i]
        remaining = a[i + 1:]
        ans = sq(remaining, target, arr + [n])
        if (ans):
            return ans
# 1000000007
mod = int(1e9) + 7
def ssinp(): return sys.stdin.readline().strip()
#s=input()
def iinp(): return int(input())
#n=int(input())
def nninp(): return map(int, sys.stdin.readline().strip().split())
#n, m, a=[int(x) for x in input().split()]
def llinp(): return list(map(int, sys.stdin.readline().strip().split()))
#a=list(map(int,input().split()))
def p(xyz): print(xyz)
def p2(a, b): print(a, b)
import math
from collections import OrderedDict
#for _ in range(iinp()):
n=iinp()
s=ssinp()
flag=0
ans=""
for c in s:
    if(ans=="" and n%2==1):
        ans+=c
    elif(flag==0):
        ans=c+ans
        flag=1
    else:
        ans=ans+c
        flag=0
p(ans)