public class Main { public static void main(String[] args) throws NumberFormatException, IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out)); int t = Integer.parseInt(reader.readLine()); boolean[] b = new boolean[t + 1]; // 1 b[0] = b[1] = false; // 2 for (int i = 2; i