#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h, i, m, l;
  string s, s1 = "";
  cin >> n >> s;
  ;
  if (n % 2 == 0) {
    for (i = n - 2; i >= 0; i -= 2) {
      cout << s[i];
    }
    for (i = 1; i < n; i += 2) {
      cout << s[i];
    }
  } else {
    for (i = n - 2; i >= 1; i -= 2) {
      cout << s[i];
    }
    for (i = 0; i < n; i += 2) {
      cout << s[i];
    }
  }
}
