#include <bits/stdc++.h>
using namespace std;
const int N = 1e8 + 5;
long long MAX = 1e9;
long long MOD = 1e9 + 7;
long long Mod = 1e9 + 7;
double EPS = 0.0001;
long long gcd(long long a, long long b) { return (b == 0 ? a : gcd(b, a % b)); }
long long lcm(long long a, long long b) { return ((a * b) / gcd(a, b)); }
const int dx[] = {1, -1, 0, 0, 0, 0};
const int dy[] = {0, 0, 1, -1, 0, 0};
int main() {
  int n;
  string s1;
  cin >> n;
  cin >> s1;
  if (n == 1 || n == 2) {
    cout << s1 << endl;
    return 0;
  }
  vector<char> ans(n, '_');
  ans[(n - 1) / 2] = s1[0];
  int indx1 = n % 2 == 0 ? n / 2 : n / 2 - 1;
  int indx2 = n % 2 == 0 ? n / 2 - 2 : n / 2 + 1;
  int dir1 = n % 2 == 0 ? 1 : -1;
  int dir2 = n % 2 == 0 ? -1 : 1;
  for (int i = 1; i <= n; i++) {
    if (i % 2 != 0 && indx1 >= 0 && indx1 < n) {
      ans[indx1] = s1[i];
      indx1 += dir1;
    }
    if (i % 2 == 0 && indx2 >= 0 && indx2 < n) {
      ans[indx2] = s1[i];
      indx2 += dir2;
    }
  }
  for (auto c : ans) cout << c;
  cout << endl;
  return 0;
}
