/*
TASK: sub
LANG: C++
*/

#include <iostream>
using namespace std;

int size, saved, stack[ 32 ];
int which, cache[ 131072 ];

void input() {
     
    cin >> which;
}

void solve() {
    
    for( int i = 1; i < 131071; ++i ) cache[i] = 8388608;     
    for( int i = 1; i < 10; ++i ) 
        cache[i] = 1;
        
    if( which < 10 ) { cout << cache[which] << endl; return; }
    
    for( int i = 10; i <= which; ++i ) {
        
        size = 0;
        saved = i;
        while( saved ) { stack[size++] = saved % 10; saved /= 10; }
        
        for( int j = 0; j < size; ++j ) {
            
            cache[i] <?= cache[i-stack[j]] + 1;      
        }        
    }
    
    cout << cache[which] << endl;
         
}

int main() {
    
    input();
    solve();
    
    return 0;    
}
