#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, mid;
  bool flag;
  string str;
  char ans[3000];
  cin >> n;
  cin >> str;
  if (n % 2 == 0) {
    mid = (n / 2) - 1;
    flag = true;
  } else {
    mid = (n - 1) / 2;
    flag = false;
  }
  long long k = 1, cnt = 0;
  ans[mid] = str[0];
  for (long long i = 1; i < str.size(); i++) {
    cnt++;
    if (flag) {
      ans[mid + k] = str[i];
    } else {
      ans[mid - k] = str[i];
    }
    if (cnt == 2) {
      k++;
      cnt = 0;
    }
    flag = !flag;
  }
  for (long long i = 0; i < n; i++) {
    cout << ans[i];
  }
  return 0;
}
