#include <bits/stdc++.h>
using namespace std;
const long long MOD = (long long)1e6;
vector<pair<long long, long long> > v;
string s;
set<string> st;
int n, m, a, b, c;
int main() {
  ios_base::sync_with_stdio(0);
  cin >> n;
  cin >> s;
  string s1;
  if (n % 2 == 1)
    for (int i = 0; i < n; i++) {
      if (i % 2 == 0)
        s1 += s[i];
      else
        s1 = s[i] + s1;
    }
  else
    for (int i = 0; i < n; i++) {
      if (i % 2 == 1)
        s1 += s[i];
      else
        s1 = s[i] + s1;
    }
  cout << s1;
  return 0;
}
