#include <bits/stdc++.h>
using namespace std;
const double eps = 0.0000001;
const int inf = 1e9 + 7;
char str[2005], vis[2055], ans[2005];
int main() {
  int n;
  scanf("%d", &n);
  scanf("%s", str + 1);
  memset(vis, 0, sizeof(vis));
  int cnt = 0;
  for (int i = n - 1; i >= 0; i -= 2) {
    if (i <= 0) {
      ans[cnt++] = str[1];
      vis[1] = 1;
      break;
    }
    vis[i] = 1;
    ans[cnt++] = str[i];
  }
  for (int i = 1; i <= n; i++)
    if (!vis[i]) ans[cnt++] = str[i];
  printf("%s\n", ans);
}
