#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  string res;
  if (n % 2 == 0) {
    for (int i = 0; i < n; ++i) {
      if (i % 2 == 0)
        res = s[i] + res;
      else
        res = res + s[i];
    }
  } else {
    for (int i = 0; i < n; ++i) {
      if (i % 2 == 0)
        res = res + s[i];
      else
        res = s[i] + res;
    }
  }
  cout << res << "\n";
}
int main() { solve(); };
