textManipulation

import java.util.Scanner;
public class TextManipulation {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        StringBuilder text = new StringBuilder();
        String command = scanner.nextLine();
        while (!command.equals("End")) {
            String[] tokens = command.split("\\s+"); // split the command by whitespace
            switch (tokens[0]) { // check the first word of the command
                case "Add": // if it is "Add"
                    text.append(tokens[1]); // append the given substring at the end of the string
                    break;
                case "Upgrade": // if it is "Upgrade"
                    char oldChar = tokens[1].charAt(0); // get the given char
                    char newChar = (char) (oldChar + 1); // get the next char in the ASCII table
                    for (int i = 0; i < text.length(); i++) { // loop through the string
                        if (text.charAt(i) == oldChar) { // if the current char matches the given char
                            text.setCharAt(i, newChar); // replace it with the next char
                        }
                    }
                    break;
                case "Print": // if it is "Print"
                    System.out.println(text); // print the string
                    break;
                case "Index": // if it is "Index"
                    char target = tokens[1].charAt(0); // get the given char
                    boolean found = false; // flag to indicate if any occurences are found
                    for (int i = 0; i < text.length(); i++) { // loop through the string
                        if (text.charAt(i) == target) { // if the current char matches the given char
                            System.out.print(i + " "); // print its index and a space
                            found = true; // set the flag to true
                        }
                    }
                    if (!found) { // if no occurences are found
                        System.out.print("None"); // print "None"
                    }
                    System.out.println(); // print a new line
                    break;
                case "Remove": // if it is "Remove"
                    String substring = tokens[1]; // get the given substring
                    int index = text.indexOf(substring); // find the first index of the substring in the string
                    while (index != -1) { // while there is a match
                        text.delete(index, index + substring.length()); // delete the substring from the string
                        index = text.indexOf(substring); // find the next index of the substring in the string
                    }
                    break;
            }
            command = scanner.nextLine(); // read the next command
        }
    }
}