What's the right approch to solve this problem?

import java.io.*;
import java.util.*;

public class Main {

       static String help(String str)
      {
           // Your code here
		  int a = 0;
		  char ch = 'e';
		  for(int i=0; i<str.length(); i++){
			  if(str.charAt(i)==ch){
				  a = a*ch;
			  }
			  return a.toString();
		  }

		 
		   
			
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String str=sc.next();
        String result = help(str);
        System.out.print(result);        
        System.out.println('\n');
    }
}