#include <bits/stdc++.h>
using namespace std;
char s[2050], t[2050];
int n;
int main() {
  scanf("%d", &n);
  scanf("%s", s + 1);
  int ret1 = n / 2, ret2, type;
  if (!(n & 1)) ret1--;
  ret2 = ret1;
  t[ret1] = s[1];
  if (n & 1)
    type = 1;
  else
    type = 2;
  for (int i = 2; i <= n; i++) {
    if (type == 1)
      t[--ret1] = s[i];
    else
      t[++ret2] = s[i];
    type = 3 - type;
  }
  printf("%s", t);
  return 0;
}
