/* 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 findStrs(int hash, int n, String s) {
    if (n==0) {
        System.out.println(s);
        return;
    }   
 
    int from = hash / n - 13 * (n-1);
    from = (from < 1)? 1: from;
    int to = (hash - (n * (n-1) / 2)) / n;
    to = (to > 26)? 26: to;
 
    for (int i = from; i<= to; i++){
        //System.out.println(i);
        findStrs(hash - i * n, n - 1, (char)(97 + i - 1) + s);   
    }
   return;
 } 
	public static void main (String[] args) throws java.lang.Exception
	{
	   findStrs(5, 2, "");	// your code goes here
	}
}

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