#include <iostream>
using namespace std;
 
int main()
{
    long long N, sum, subsidiary = 0, quantity = 0;
    cin >> N;
    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++;
    }
    cout << quantity << endl;
    return 0;
}