public class Main {


    private static String createAcronimFromString(String input){
        StringBuilder outString = new StringBuilder();
        String[] afterSplit = input.split(" ");
        for(int i = 0; i < afterSplit.length; ++i){
            char ch = afterSplit[i].charAt(0);
            outString.append(Character.toLowerCase(ch));
        }
        return outString.toString();
    }

    public static void main(String[] args) {
        String string = "test string xd";
        System.out.println(createAcronimFromString(string));
    }
}