Counting the number of vowels in a string

import java.util.Scanner;
class CountingVowels{
        public static void main(String args[]){
                Scanner sc = new Scanner(System.in);
                System.out.print("Enter a string: ");
                String string = sc.nextLine();
                string = string.toLowerCase();
                int counter = 0;
                for(int i = 0; i < string.length(); i++)
                        if(string.charAt(i) == 'a' || string.charAt(i) == 'e' || string.charAt(i) == 'i' || string.charAt(i) == 'o' || string.charAt(i) == 'u')
                                counter++;
                System.out.println("The number of vowerls are "+counter);
        }
}