I need a main method for the following JAVA program:

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public class LetterInventory{ private int size; private int[] elementData; private String original; public static final int DEFAULT_CAPACITY = 26; // constructs an inventory for the given string input, and the // total count of letters will be recorded public LetterInventory(String data){ elementData = new int[DEFAULT_CAPACITY]; data = data.toLowerCase(); original = data; for (int i = 0; i < data.length(); i++){ if (Character.isLetter(data.charAt(i))){ elementData[data.charAt(i) - 'a']++; if(data.charAt(i) == 'q'){ elementData['u' - 'a']++; } size++; } } } // return the total number of characters in the inventory public int size(){ return size; } public String getOriginal(){ return original; } // return true if the inventory is empty public boolean isEmpty(){ return size == 0; } //return the count of given character in the inventory //IllegalArgumentException when the letter is a nonalphabetic letter public int get(char letter){ if (!Character.isLetter(letter)) throw new IllegalArgumentException("letter: " + letter); return elementData[Character.toLowerCase(letter) - 'a']; } // return a string of sorted letter of alphabet, surrounded with square brackets public String toString(){ String result = "["; for (int i = 0; i < DEFAULT_CAPACITY; i++){ for (int j = 0; j < elementData[i]; j++) result += (char)('a' + i); } return result + "]"; } // take in a character and an integer, change the number of count for a single aplhabeet //IllegalArgumentException when the letter is a nonalphabetic letter or when it is negative public void set(char letter, int value){ if (!Character.isLetter(letter) || value < 0) throw new IllegalArgumentException("letter: " + letter + ", value: " + value); size += value - elementData[Character.toLowerCase(letter) - 'a']; elementData[Character.toLowerCase(letter) - 'a'] = value; } //return a LetterInventory object which is the sum of other two LetterInventory objects public LetterInventory add(LetterInventory other){ LetterInventory sum = new LetterInventory(""); for (int i = 0; i < DEFAULT_CAPACITY; i++) sum.elementData[i] = this.elementData[i] + other.elementData[i]; sum.size = this.size + other.size; return sum; } // return a LetterInventory object of difference of other two // null LetterInventory object will be returned if any letter's difference less than 0 public LetterInventory subtract(LetterInventory other){ LetterInventory result = new LetterInventory(""); for (int i = 0; i < DEFAULT_CAPACITY; i++){ result.elementData[i] = this.elementData[i] - other.elementData[i]; if (result.elementData[i] < 0) return null; result.size += result.elementData[i]; } return result; } }