/*
 * To input two sorted arrays ,merge them into a third array,which should also be sorted
 * @author-Karan Narain(karan@iitk.ac.in)
 *
*/

#include <stdio.h>
//sum is the function which recursively calculates the sum of the digits of the number n
int sum(int n)
{
	if(n==0)
	return 0;
	else 
	return (n%10+sum(n/10));


}
//sumrec is the function which recursively calculates the sum of digits till the sum becomes a single-digit number,by calling sum() 
void sumrec(int n)
{
	printf("The sum of digits of %d is",n); 
	n=sum(n);
	printf(" %d\n",n);
	//If the sum has more than 1 digit,make a recursive call
	if(n/10!=0)
	sumrec(n);
	else 
	return;
}

int main()
{
	int n,s;
	printf("Enter the number\n");
	scanf("%d",&n);
	sumrec(n);
	return 0;
}