Deleting digits

#include <iostream>
#include <vector>
using namespace std;

int getHighestDigit(int n){
    int d=0;
    while (n>0){
        d=max(n%10, d);
        n/=10;
        if (d==9){
            return 9;
        }
    }
    return d;
}

int main(){
    int n;
    cin >> n;
    int c=0;
    while (n>0){
        n-=getHighestDigit(n);
        c++;
    }
    cout << c << '\n';
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED