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 PYTHON3):

Solution:
'''#Problem Code: PROC18A
n = int(input())
for i in range(n):
    m = list(map(int,input().split()))
    lst = list(map(int,input().split()))
    sum1=0
    l1=[]
    for k in range(m[0]-1):
    	for k in range(k,k+m[1]):
    	    sum1+=lst[k]
    	l1.append(sum1)
    	sum1=0
    print(max(l1))


#Problem Code: RD19
import math

def gcdchk(data,j):
    if j >= m - 1:
        return -1
    else:

        l2 = math.gcd(data, lst[j + 1])
        gcdchk(l2, j + 1)
        return l2

n = int(input())
for i in range(n):
    m = int(input())
    lst=list(map(int,input().split()))
    l1 = math.gcd(lst[0], lst[1])
    ans = gcdchk(l1, 1)
    if ans == 1:
        print("0")
    else:
        print("-1")

#Problem Code: BFTT
t=int(input())
for x in range(t):
  n=int(input())
  n=n+1
  while (str(n).count('3'))<3:
    n+=1
  print(n)
'''
'''
#Problem Code: COGNIF03

t = int(input())
for i in range(t):
    s = input()
    m,n= input().split()
    print(m,n)
    s = s*int(m)
    srt = "".join(sorted(list(s)))
    print(srt)
    lst=[]
    for j in range(int(n)):
        lst.append(int(input()))
    mx = max(lst)
    for i in lst:
        if i > len(srt):
            print("-1")
        else:
            print(srt[i-1])


#Problem Code: MANIP6
'''

'''
#Problem Code: TAEDITOR
n = int(input())
s=""
for i in range(n):
    x = input().split()
    if x[0] == '+':
        s=s[:int(x[1])]+x[2]+s[int(x[1]):]
    else:
        print(s[(int(x[1])-1):((int(x[2])+int(x[1])-1))])
'''

'''#Problem Code:HS08TEST
n,m = map(float,input().split())
if n+0.50<=m:
    if n % 5 == 0:
        print("%.2f" % (m - n - 0.5))
    else : print("%.2f" % (m))
else: print("%.2f" % (m))'''

#PC:HOWMANY
# n = len(input())
# if n==1:
#     print("1")
# elif n==2:
#     print("2")
# elif n==3:
#     print("3")1

# else:print("More than 3 digits")

''''#PC:RECTANGL
n = int(input())
for i in range(n):
    lst = list(map(int,input().split()))
    lst = sorted(lst)
    if lst[0] == lst[1] and lst[2] == lst[3]:
        print("YES")
    else: print("NO")'''


#Pangram
# n=int(input())
# lst=input()
# lst=lst.lower()
# if n>25:
#     l1="abcdefghijklmnopqrstuvwxyz"
#     data=list(l1)
#     lst1=[]
#     for i in lst:
#         if i in data:
#             if i not in lst1:
#                 lst1.append(i)
#                 data.remove(i)
#     if len(lst1)==26:
#         print("YES")
#     else: print("NO")
# else: print("NO")


#Word
# data=input()
# l1,l2=0,0
# for i in data:
#     if ord(i)>90:
#         l1+=1
#     else: l2+=1
# if l1==l2:
#     print(data.lower())
# else: print(data.upper())

#
# #Interviewbit
# from itertools import combinations
# n=[-2,1,-3,4,-1,2,1,-5,4]
# l=len(n)
# lst=[[]]
# for i in range(l + 1):
#     for j in range(i + 1, l + 1):
#         sub = n[i:j]
#         lst.append(sub)
# data=[]
# print(lst)
# for i in lst:
#     data.append(sum(i))
# print(data)
# print(max(data))

#
# n=[1,4,6,8,3,10,2,5,6,9]
# n=sorted(n)
# low=0
# high=len(n)-1
# while low<=high:
#     mid=(low+high)//2
#     print(mid+1,n[mid])
#     high=mid

#Interviewbit  :-  Largest Number
# A=[3, 30, 34, 5, 9]
# lst=[]
# for i in A:
#     if i<10:
#         lst.append(i)
#     else:
#         val=((int(x)) for  x  in str(i))
#         for j in val:
#             lst.append(j)
# lst=sorted(lst,reverse=True)
# val="".join(str(x) for x in lst)
# print(val)
#Correct Solution
# def comparator(a, b):
#     ab = str(a) + str(b)
#     ba = str(b) + str(a)
#     return ((int(ba) > int(ab)) - (int(ba) < int(ab)))
# def myCompare(mycmp):
#     class K(object):
#         def __init__(self, obj, *args):
#             self.obj = obj
#         def __lt__(self, other):
#             return mycmp(self.obj, other.obj) < 0
#         def __gt__(self, other):
#             return mycmp(self.obj, other.obj) > 0
#         def __eq__(self, other):
#             return mycmp(self.obj, other.obj) == 0
#         def __le__(self, other):
#             return mycmp(self.obj, other.obj) <= 0
#         def __ge__(self, other):
#             return mycmp(self.obj, other.obj) >= 0
#         def __ne__(self, other):
#             return mycmp(self.obj, other.obj) != 0
#     return K
# class Solution:
#     def largestNumber(self, a):
#         if a.count(0)==len(a):
#             return 0
#         else:
#             sorted_array = sorted(a, key=myCompare(comparator))
#             number = "".join([str(i) for i in sorted_array])
#             return (number)

#CodeForces
# n=int(input())
# data=sum(list(map(int,input().split())))
# if data%4==0:
#     print(data//4)
# else:
#     print(data//4+1)



#codechef
# T=int(input())
# while T>0:
#     n=int(input())
#     lst,lst1=[],[]
#     for i in range(n):
#         lst.append(tuple(list(map(int,input().split()))))
#     m = int(input())
#     for i in range(m):
#         lst1.append(tuple(list(map(int,input().split()))))
#     sum1=0
#     for i in lst1:
#         for j in lst:
#             if i[0]<j[0]:
#                 sum1+=i[1]
#                 if sum1<j[1]:
#                     print("Go Sleep")
#                     break
#                 else:
#                     print("Go Camp")
#                     break
#             else:
#                 sum1+=i[1]
#     T-=1

#Codeforces Right-Left Cipher
n=(input())
s=""
if len(n)%2==0:
    y=len(n)-1
    x=0
    while x<=y:
        s=s+n[y]
        s=s+n[x]
        y-=1
        x+=1
    print(s[::-1])
else:
    y = len(n) - 1
    x = 0
    while x < y:
        s = s + n[x]
        s = s + n[y]
        y -= 1
        x += 1
    print(n[x] + s[::-1])