/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		List<Character> chars = new ArrayList<Character>(Arrays.asList('a','e','i','o','u'));
		List<Character> charsInString = new ArrayList<Character>();
		String test = "this is a test string";
 
		for (char a: test.toCharArray()) {
			if (chars.indexOf(a) > -1) {
				if (charsInString.indexOf(a) == -1) {
					charsInString.add(a);
				}
			}
		}
 
		System.out.println(charsInString.size());
	}
}

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