https://www.e-olymp.com/az/problems/20

#include <iostream>
/*
    Author: Kanan Asgarli
    https://www.e-olymp.com/az/problems/20
*/
using namespace std;
int sum_of_digits(int n){
    int sum = 0;
    while(n > 0){
        sum += n%10;
        n = n/10;
    }
    return sum;
}
int n, ans;
int main() {
    cin>>n;
    while(n > 0){
        ans++;
        n = n - sum_of_digits(n);
    }
    cout<<ans<<endl;
    return 0;
}