/*Program to find the nummber of applications of sqn function needed to reach 1 or 89 for a given number.
sqn function applied on a function returns the sum of squares of digits of a number*/
#include<stdio.h>

int sqn(int);//Prototype for sqn

int main()
{
	int n,tmp,depth=0;
	scanf("%d",&n);
	tmp = n;
	while(tmp!=1 && tmp!=89)
	{
		tmp = sqn(tmp);
		depth++;
	}
	printf("Depth of %d is %d\n",n,depth);
return 0;
}

int sqn(int m)
{
	int result=0,digit;
	while(m > 0)
	{
		digit = m%10;
		result += digit*digit;
		m = m/10;
	}
return result;
}