/* 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
	{
		ArrayList<Integer> v = new ArrayList();
		v.add(2);
		v.add(0);
		v.add(4);
		v.add(3);
		v.add(1);
 
		for (int i = 0; i<=3; i++){
			for (int j = 0; j<=3-i; j++){
				if(v.get(j)>v.get(j+1)){
					system.out.println(i+"_"+j)
				}
				}
			}
		}
	}
}

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