#include <bits/stdc++.h>
using namespace std;
vector<char> v;
int main() {
  int n;
  scanf("%d", &n);
  string s;
  getchar();
  getline(cin, s);
  int sum = n - 1;
  v.push_back(s[0]);
  for (int i = 1; i < n; i++) {
    if (sum % 2 == 0)
      v.insert(v.begin(), s[i]);
    else
      v.push_back(s[i]);
    sum--;
  }
  for (int i = 0; i < n; i++) {
    printf("%c", v[i]);
  }
  return 0;
}
