#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  string s, decoded;
  cin >> n >> s;
  decoded = s;
  int i, j, p = 0;
  if (s.size() % 2 == 1) {
    decoded[s.size() / 2] = s[0];
    ++p;
    j = s.size() / 2 + 1;
  } else {
    j = s.size() / 2;
  }
  i = s.size() / 2 - 1;
  while (p < s.size()) {
    decoded[i] = s[p++];
    decoded[j] = s[p++];
    --i;
    ++j;
  }
  cout << decoded << endl;
  return 0;
}
