// Read in a positive integer and sum up its digits to reduce it to a
// new integer, repeating the process until only a single digit
// remains.
//
// Example: user enters 8974
// 8974 reduces to 28 which reduces to 10 which reduces to 1

public class ReduceInteger {
    
    public static void main(String[] args) {
	
	int number, sum;
	
	// read in the number to reduce
	// assume the input is positive
	TokenReader in = new TokenReader(System.in);
	System.out.println("Enter a number to be reduced:");
	number = in.readInt();
	
	// leave a blank line and repeat the starting value
	System.out.println();
	System.out.println("Starting value: " + number);
	
	// reduce the current number until it is a single digit
	while (number > 9) {
	    sum = 0;
	    
	    // add up the digits of the current number
	    // assume sum == 0 to start
	    while (number > 9) {
		sum = sum + (number % 10);
		number = number / 10;
	    }
	    
	    sum = sum + number;
	    number = sum;
	    System.out.println("Reduces to: " + number);
	}
	
	System.out.println("Done!");
	
    }
    
}