text: 
  // Problem: B. Decoding
  // Contest: Codeforces - Codeforces Round #386 (Div. 2)
  // URL: https://codeforces.com/problemset/problem/746/B
  // Memory Limit: 256 MB
  // Time Limit: 1000 ms
  // Powered by CP Editor (https://github.com/cpeditor/cpeditor)
  
  #include <bits/stdc++.h>
  #define F first
  #define S second
  #define PB push_back
  #define MP make_pair
  #define ll long long int
  #define vi vector<int>
  #define vii vector<int, int>
  #define vc vector<char>
  #define vl vector<ll>
  #define mod 1000000007 
  #define INF 1000000009
  using namespace std;
  
  
  int main()
  {
       ios_base::sync_with_stdio(0);
       cin.tie(0);
       cout.tie(0);
       
       int n;
       cin >> n;
       string s;
       cin >> s;
  	if(n % 2 != 0)     {
  		
  	
       for(int i = n- 2; i >= 0; i -= 2 ) {
       	cout << s[i];
       }
       
       for(int i = 0 ; i < n ; i = i+2) {
       	cout << s[i];
       }
       cout << "\n";
      } 
      else {
   	for(int i = n- 2; i >= 0; i -= 2 ) {
       	cout << s[i];
       }
       
       for(int i = 1 ; i < n ; i = i+2) {
       	cout << s[i];
       }
       cout << "\n";
      } 
       
  return 0;
  }