#include <bits/stdc++.h>
using namespace std;
const int N = 2e3 + 5, OO = 0x3f3f3f3f;
int n;
char s[N];
deque<int> tmp;
int main() {
  scanf("%d", &n);
  scanf("%s", s);
  if (n == 1 || n == 2) {
    printf("%s\n", s);
    return 0;
  }
  tmp.push_back(s[0]);
  for (int i = 1; i < n; i++) {
    if ((i) % 2 == 0) {
      tmp.push_back(s[i]);
    } else {
      tmp.push_front(s[i]);
    }
  }
  if (n % 2 != 0) {
    for (int i = 0; i < tmp.size(); i++) {
      printf("%c", tmp[i]);
    }
  } else {
    for (int i = tmp.size() - 1; i >= 0; i--) {
      printf("%c", tmp[i]);
    }
  }
  printf("\n");
  return 0;
}
