#include <bits/stdc++.h>
using namespace std;
int main() {
  char s1[2005], s2[2005];
  int n, i;
  scanf("%d", &n);
  getchar();
  for (i = 1; i <= n; i++) scanf("%c", &s1[i]);
  if (n % 2 == 0) {
    int x = n / 2, y = n / 2 + 1;
    for (i = 1; i <= n; i += 2) {
      s2[x--] = s1[i];
      s2[y++] = s1[i + 1];
    }
    for (i = 1; i <= n; i++) printf("%c", s2[i]);
  } else {
    int x = n / 2, y = n / 2 + 2;
    s2[x + 1] = s1[1];
    for (i = 2; i <= n; i += 2) {
      s2[x--] = s1[i];
      s2[y++] = s1[i + 1];
    }
    for (i = 1; i <= n; i++) printf("%c", s2[i]);
  }
  puts("");
  return 0;
}
