#include <bits/stdc++.h>
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;
  char arr[n + 10];
  if (n % 2 == 1) {
    int temp = n / 2;
    int j = 0;
    int k = 1;
    for (int i = 0; i < (int)s.size(); i++) {
      if (i % 2 == 0) {
        arr[temp + j++] = s[i];
      } else {
        arr[temp - k++] = s[i];
      }
    }
    string ans(arr, arr + n);
    cout << ans << endl;
  } else {
    int temp = n / 2 - 1;
    int j = 0;
    int k = 1;
    for (int i = 0; i < (int)s.size(); i++) {
      if (i % 2 == 0) {
        arr[temp - j++] = s[i];
      } else {
        arr[temp + k++] = s[i];
      }
    }
    string ans(arr, arr + n);
    cout << ans << endl;
  }
  return 0;
}
