n = int(input())
def f(num):
num += 1
while num % 10 == 0:
num //= 10
return num
dostizh_nums = set()
while n not in dostizh_nums:
dostizh_nums.add(n)
n = f(n)
print(len(dostizh_nums))#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define el '\n'
#define ll long long
#ifndef ONLINE_JUDGE
#include "Debug.cpp"
#else
#define debug(...) 42
#endif
void solve ( ) {
int n;cin>>n;
ll cnt = 9 ;
while(n>=10)
{
cnt+=10-n%10 ;
n+=10-n%10 ;
while(n%10==0) {
n/=10 ;
}
}
cout<<cnt<<el ;
}
int main ( ) {
ios_base::sync_with_stdio ( 0 );
cin.tie ( 0 );
cout.tie ( 0 );
int t = 1;
// cin >> t;
for ( int i = 0; i < t; i ++ ) {
solve ( );
}
}
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1256A - Payment Without Change | 908B - New Year and Buggy Bot |
979A - Pizza Pizza Pizza | 731A - Night at the Museum |
742A - Arpa’s hard exam and Mehrdad’s naive cheat | 1492A - Three swimmers |
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1230B - Ania and Minimizing | 1201A - Important Exam |
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1223A - CME | 1658B - Marin and Anti-coprime Permutation |
14B - Young Photographer | 143A - Help Vasilisa the Wise 2 |
320A - Magic Numbers | 1658A - Marin and Photoshoot |
514A - Chewbaсca and Number | 382A - Ksenia and Pan Scales |