public static String convert(String str) {
str = str.replaceAll("à|á|ạ|ả|ã|â|ầ|ấ|ậ|ẩ|ẫ|ă|ằ|ắ|ặ|ẳ|ẵ", "a");
str = str.replaceAll("è|é|ẹ|ẻ|ẽ|ê|ề|ế|ệ|ể|ễ", "e");
str = str.replaceAll("ì|í|ị|ỉ|ĩ", "i");
str = str.replaceAl...