#include <bits/stdc++.h>
using namespace std;
#pragma comment(linker, "/STACK:1024000000,1024000000")
int _MAX(int a, int b) { return a > b ? a : b; }
int _MIN(int a, int b) { return a > b ? b : a; }
int Scan() {
  int res = 0, flag = 0;
  char ch;
  if ((ch = getchar()) == '-')
    flag = 1;
  else if (ch >= '0' && ch <= '9')
    res = ch - '0';
  while ((ch = getchar()) >= '0' && ch <= '9') res = res * 10 + (ch - '0');
  return flag ? -res : res;
}
void Out(int a) {
  if (a < 0) {
    putchar('-');
    a = -a;
  }
  if (a >= 10) Out(a / 10);
  putchar(a % 10 + '0');
}
char s[2005], ans[2005];
int main() {
  int n, cnt = 0;
  scanf("%d", &n);
  scanf("%s", s);
  int now = (n - 1) / 2;
  ans[now] = s[cnt++];
  if (n & 1) {
    for (int i = 1; now - i >= 0 || now + i < n; ++i) {
      if (now - i >= 0) ans[now - i] = s[cnt++];
      if (now + i < n) ans[now + i] = s[cnt++];
    }
  } else {
    for (int i = 1; now - i >= 0 || now + i < n; ++i) {
      if (now + i < n) ans[now + i] = s[cnt++];
      if (now - i >= 0) ans[now - i] = s[cnt++];
    }
  }
  ans[n] = '\0';
  puts(ans);
  return 0;
}
