#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  char s[n];
  char b[n];
  cin >> s;
  if (n % 2 != 0) {
    int i = 0;
    b[n / 2] = s[i];
    int j = 1;
    for (i = 1; i < n; i += 2) {
      b[n / 2 - j] = s[i];
      b[n / 2 + j] = s[i + 1];
      j++;
    }
    for (int i = 0; i < n; i++) {
      cout << b[i];
    }
  } else if (n % 2 == 0) {
    int i = 0;
    b[n / 2] = s[0];
    int j = 1;
    for (i = 1; i < n; i += 2) {
      b[n / 2 - j] = s[i];
      b[n / 2 + j] = s[i + 1];
      j++;
    }
    for (int i = n - 1; i >= 0; i--) {
      cout << b[i];
    }
  }
}
