Lang:Java
Edit12345678910111213141516171819202122232425262728293031import java.util.Scanner;/*** This is the ACM problem solving program for TaiGe Algorithm contest problem* B.** @version 2016-12-22* @author Zhang Yufei*/public class Main {private static final int MOD = 1000000007;private static int N;private static int max = -1;/*** The main program.** @param args* The command-line parameters list.*/public static void main(String[] args) {Scanner scan = new Scanner(System.in);N = scan.nextInt();scan.close();if(N <= 20) {search(0, 0, 1);System.out.println(max);} else {System.out.println(search(N));