#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
const long long INF = (1LL << 60);
const long long mod = 1000000007;
const double Pi = acos(-1.0);
const int maxn = 2e5 + 5;
char s[maxn];
char ans[maxn];
int main() {
  ios::sync_with_stdio(false);
  int n;
  cin >> n >> s;
  if (n & 1) {
    int mid = n / 2;
    ans[mid] = s[0];
    int l = mid - 1, r = mid + 1;
    int cnt = 1;
    while (cnt < n) {
      ans[l--] = s[cnt++];
      ans[r++] = s[cnt++];
    }
    cout << ans << endl;
  } else {
    int mid = n / 2;
    int l = mid - 1, r = mid;
    int cnt = 0;
    while (cnt < n) {
      ans[l--] = s[cnt++];
      ans[r++] = s[cnt++];
    }
    cout << ans << endl;
  }
}
