Java Count Substracting Occurances

import java.util.Scanner;


public class CountSubstringOccurances {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String sentence = in.nextLine().toLowerCase();
        String word = in.nextLine().toLowerCase();
        int counter = 0;

        for (int i = 0; i <= sentence.length() - word.length(); i++) {
            if (sentence.substring(0 + i, word.length() + i).contains(word)) {
                counter++;
            }
        }
        System.out.println(counter);
    }
}