Pretty-printed 1-3-sum

public class test {
    public static void main(String[] args){
        @SuppressWarnings("resource")
        String str = new java.util.Scanner(System.in).next();
        int num = 0;

        for (int i = 0; i < str.length(); i++){
            int multiplier = i % 2 == 0 ? 1 : 3;
            num += Integer.parseInt(str.substring(i, i + 1)) * multiplier;
        }

        String numValidity = num % 10 == 0 ? "Your number is okay" : "Your number is invalid";
        System.out.printf("The 1-3-sum is %d.\n%s", num, numValidity);
    }
}