public class Base64{

    public static int getBase64ByteSize(String str){
      String[] specialSigns = new String[] {"\u00C4","\u00E4","\u00D6"};

      int amountspecialSigns = countSpecialSigns(str, specialSigns);

      int n = str.length();

      int z = 4 * (int) Math.ceil( (double) n/3);

      return z;
    }

    public static int countSpecialSigns(String str, String[] specialSigns){
        int count = 0;
        for (int i=0; i < str.length(); i++){
          for (int l=0; l< specialSigns.length; l++){
              if (str.charAt(i).toString() == specialSigns[l]){
                   count++;
              }
          }
        }
        return count;
    }




    public static void main(String[] args){

      System.out.println(getBase64ByteSize("Hällo"));
    }
  }