/* 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
	{
		// your code goes here
		String accountNumber = "327231123";
		String replacedByX = "";
		for(int i = 0; i < accountNumber.length() - 4; i++) {
			replacedByX += "x";
		}
		replacedByX += accountNumber.substring(accountNumber.length() - 4);
 
		System.out.println(replacedByX);
	}
}

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