#include <bits/stdc++.h>
using namespace std;
char input_buf[2048];
char output_buf[2048];
int main(int argc, char *argv[]) {
  int length;
  scanf("%d", &length);
  scanf("%s", input_buf);
  int i = 0;
  int ptr = length - 2;
  while (ptr > 0) {
    output_buf[i++] = input_buf[ptr];
    ptr -= 2;
  }
  output_buf[i++] = input_buf[0];
  ptr = ((length)&1) ? 2 : 1;
  while (ptr < length) {
    output_buf[i++] = input_buf[ptr];
    ptr += 2;
  }
  output_buf[i] = 0;
  printf("%s\n", output_buf);
  return 0;
}
