import java.util.Scanner;
public class TextProcessing {
    public static void main(String[] args) {
        String sentence, wordToBeTargeted, wordToBeReplaced, output;
        boolean wordToCheck;
        Scanner myInput = new Scanner(System.in);
        sentence = myInput.nextLine();
        do {
            wordToCheck = true;
            System.out.println("Please enter the word for replacement:");
            wordToBeTargeted = myInput.nextLine();
            if (sentence.toLowerCase().indexOf(wordToBeTargeted.toLowerCase()) == -1) {
                wordToCheck = false;
                System.out.println("This word cannot be found in the sentence!");
            } else {
                System.out.println("Please enter the word you would like to replace with:");
                wordToBeReplaced = myInput.nextLine();
                sentence = sentence.replaceAll("(?i)" + wordToBeTargeted, wordToBeReplaced);
                System.out.println(sentence);
            }
        } while (wordToCheck == false);
    }
}