#!/usr/bin/gawk -f


/^\[[0-9]+a\] / {
  if(!n || (n % 27) == 0 || runon) {
    if ($0 ~ /<p>/) {
      output = 0;
      runon = 1;
    }
    else {
      output = 1;
      runon = 0;
      if(n) printf("\n");
      print;
    }
  }
  else {
    output = 0;
    runon = 0;
  }
  n++;
}


/^\[[0-9]+[bcd]\] / {
  if(output) print;
}