求本题Java解法

import java.util.Scanner;
public class Main{
    public static void main(String[]args){
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        boolean b = false;
        if(a % 3 == 0){
            System.out.println("3");
            b = true;
        }
        if(a % 5 == 0){
            System.out.println("5");
            b = true;
        }
        if(a % 7 == 0){
            System.out.println("7");
            b = true;
        }
        if(b == false){
            System.out.println("n");
            }
    }
}