#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, x;
  vector<int> v, ans;
  string s;
  cin >> n >> s;
  for (int i = 0; i < n; i++) v.push_back(i);
  int m = n;
  for (int i = 0; i < n; i++) {
    if (m % 2 == 0)
      x = m / 2 - 1;
    else
      x = m / 2;
    ans.push_back(v[x]);
    v.erase(v.begin() + x);
    m--;
  }
  char c[n];
  for (int i = 0; i < n; i++) c[ans[i]] = s[i];
  for (int i = 0; i < n; i++) cout << c[i];
}
