#include <bits/stdc++.h>
using namespace std;
long long mod = 1000000007;
bool isPrime(long long n);
long long power(long long x, long long y);
long long gcd(long long a, long long b);
long long lcm(long long a, long long b);
void solve() {
  deque<char> q{};
  string s{};
  long long n{};
  cin >> n >> s;
  if (n % 2 == 1) {
    for (long long i = 0; i < n; i++) {
      if (i % 2 == 0) {
        q.push_back(s[i]);
      } else {
        q.push_front(s[i]);
      }
    }
  } else {
    for (long long i = 0; i < n; i++) {
      if (i % 2 == 1) {
        q.push_back(s[i]);
      } else {
        q.push_front(s[i]);
      }
    }
  }
  for (auto it : q) {
    cout << it;
  }
  return;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long testcase = 1;
  while (testcase--) solve();
  cerr << "time taken : " << (float)clock() / CLOCKS_PER_SEC << " secs" << endl;
}
bool isPrime(long long n) {
  if (n == 1) return false;
  if (n == 2 || n == 3) return true;
  if (n % 2 == 0 || n % 3 == 0) return false;
  for (long long i = 5; i * i <= n; i = i + 6) {
    if (n % i == 0 || n % (i + 2) == 0) return false;
  }
  return true;
}
long long power(long long x, long long y) {
  if (y == 0)
    return 1;
  else if (y % 2 == 0)
    return ((power(x, y / 2) % mod) * (power(x, y / 2) % mod)) % mod;
  else
    return ((((x % mod) * ((power(x, y / 2) % mod))) % mod *
             (power(x, y / 2) % mod)) %
            mod) %
           mod;
}
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long lcm(long long a, long long b) { return (a * b) / gcd(a, b); }
