#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  string s;
  cin >> n >> s;
  string r = s;
  int mid = (n - 1) / 2;
  int i = 0;
  r[mid] = s[i++];
  if (n & 1) {
    for (int j = 1; j <= n / 2; ++j) {
      r[mid - j] = s[i++];
      r[mid + j] = s[i++];
    }
  } else {
    for (int j = 1; j <= n / 2; ++j) {
      r[mid + j] = s[i++];
      if (j == n / 2) break;
      r[mid - j] = s[i++];
    }
  }
  cout << r << '\n';
  return 0;
}
