#include <stdio.h>
#include <string.h>

int main(void)
{
  int i, j, k, half;
  char str[256], finlaStr[256];
  scanf("%s", str);

  half = strlen(str)/2;

  if(strlen(str) % 2) j = half+1;
  else j = half;

  for(i = 0, k = 0; i < half; i++, j++, k += 2)
  {
    finlaStr[k] = str[i];
    finlaStr[k+1] = str[j];
  }

  if(strlen(str) % 2)
  {
    finlaStr[k] = str[i];
    finlaStr[k+1] = '\0';
  }
  else finlaStr[k] = '\0';


  printf("%s\n", finlaStr);

  return 0;
}