/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		System.out.println("ABC321".matches("[A-Za-z0-9]+/?[A-Za-z0-9]*"));
	    System.out.println("ABC321/OTHER888".matches("[A-Za-z0-9]+/?[A-Za-z0-9]*"));
        System.out.println("ABC321/".matches("[A-Za-z0-9]+/?[A-Za-z0-9]*"));
        System.out.println("/ABC321".matches("[A-Za-z0-9]+/?[A-Za-z0-9]*"));
        System.out.println("ABC321/OTHER888/".matches("[A-Za-z0-9]+/?[A-Za-z0-9]*"));
	}
}

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