#include <bits/stdc++.h>
int main() {
  char s[2000];
  char p[2000];
  int k, i, m, n, l, j, u, r, t, f, v;
  scanf("%d\n", &n);
  scanf("%s", s);
  l = n - 1;
  f = 0;
  m = (l + f) / 2;
  v = m;
  p[m] = s[0];
  if (n % 2 != 0) {
    for (i = 1; i < n && m >= 0; i = i + 2) {
      p[m - 1] = s[i];
      m--;
    }
    j = v + 1;
    for (t = 2; t < n && j <= l; t = t + 2) {
      p[j] = s[t];
      j++;
    }
    for (i = 0; i < n; i++) printf("%c", p[i]);
  } else {
    p[m] = s[0];
    r = m;
    for (i = 2; i <= n - 1 && m >= 0; i = i + 2) {
      p[m - 1] = s[i];
      m--;
    }
    for (t = 1; t < n && r <= l; t = t + 2) {
      p[r + 1] = s[t];
      r++;
    }
    for (i = 0; i < n; i++) printf("%c", p[i]);
  }
}
