[Java] Combination Lock

/* Use the slash-star style comments or the system won't see your
   identification information */
/*
ID: lincans1
LANG: JAVA
TASK: combo
*/
import java.io.*;
import java.util.*;

public class combo {
    
    

	private void count(int N, BufferedReader f, Set<String> set) throws IOException {
    
    
		StringTokenizer st = new StringTokenizer(f.readLine());
		int a1 = Integer.parseInt(st.nextToken());
		int a2 = Integer.parseInt(st.nextToken());
		int a3 = Integer.parseInt(st.nextToken());
		for (int i = -2; i <= 2; i++) {
    
    
			for (int j = -2; j <= 2; j++) {
    
    
				for (int k = -2; k <= 2; k++) {
    
    
					set.add("" + 
					((a1 + i + N) % N + 1) + 
					((a2 + j + N) % N + 1) + 
					((a3 + k + N) % N + 1)
					);
				}
			}
		}
	}

	public combo() throws IOException {
    
    
		// Use BufferedReader rather than RandomAccessFile; it's much faster
		BufferedReader f = new BufferedReader(new FileReader("combo.in"));
		PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("combo.out")));
		int N = Integer.parseInt(f.readLine());
		Set<String> set = new HashSet<>();

		// count Farmer john's combination
		count(N, f, set);

		// count the master combination
		count(N, f, set);
		
		out.println(set.size());
	    out.close();                                  // close the output file
	}
	
	public static void main (String [] args) throws IOException {
    
    
		new combo();
	}
}