#include <bits/stdc++.h>
using namespace std;
vector<char> ans, v;
int a[5000];
char ch[5000], c[5000];
int main() {
  int n;
  scanf("%d", &n);
  int num = 1, left = n / 2, right = left + 1;
  if (n % 2) {
    a[num++] = (n + 1) / 2;
    right = (n + 1) / 2 + 1;
  }
  while (num <= n) {
    a[num++] = left--;
    a[num++] = right++;
  }
  for (int i = 1; i <= n; i++) scanf(" %c", &ch[i]);
  for (int i = 1; i <= n; i++) c[a[i]] = ch[i];
  for (int i = 1; i <= n; i++) printf("%c", c[i]);
  return 0;
}
