import java.util.*;
import java.lang.*;
import java.io.*;

class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
		long N, sum, subsidiary = 0, quantity = 0;
    	Scanner in = new Scanner(System.in);
    	N = in.nextLong();
    	while (N > 999999999) {
        	sum = 0;
        	subsidiary = N;
        	while (subsidiary!=0) {
            	sum += subsidiary%10;
            	subsidiary /= 10;
        	}
        	N -= sum;
        	quantity++;
    	}
    	if (N == 999999999) {
        	N = 0;
        	quantity += 25632473;
    	}
    	while (N > 0) {
        	sum = 0;
        	subsidiary = N;
        	while (subsidiary != 0) {
            	sum += subsidiary%10;
            	subsidiary /= 10;
        	}
        	N -= sum;
        	quantity++;
    	}
    	System.out.println(quantity);
	}
}