package code;

public class SuperDigitJava {


    //We define super digit of an integer x using the following rules:
    //If x has only 1 digit, then its super digit is x.
    //Otherwise, the super digit of x is equal to the super digit of the digit-sum of x.
    //Here, digit-sum of a number is defined as the sum of its digits.
    public static void main(String[] args) {
    	//Integer x = 1;
    	Integer x = 99;
    	System.out.println(getSuperDigit(x));

    }

	public static Integer getSuperDigit(Integer x) {
		if(x < 10) {
    		return x;
    	} else {
    		Integer digitSum = 0;
    		for (char num : x.toString().toCharArray()) {
				digitSum += Character.getNumericValue(num);
			}
    		return getSuperDigit(digitSum);
    	}
	}

}