#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

int main(){
    string s;   cin >> s;
    int sum=0;
    for(int i=0; i<s.size(); i++)
        sum += s[i]-'0';
    sum = max(sum, (s[0]-'0'-1)+9*(int)(s.size()-1));
    cout << sum << endl;
}
    

### Prompt

Please create a solution in CPP to the following problem:

Find the maximum possible sum of the digits (in base 10) of a positive integer not greater than N.

Constraints

* 1\leq N \leq 10^{16}
* N is an integer.

Input

Input is given from Standard Input in the following format:


N


Output

Print the maximum possible sum of the digits (in base 10) of a positive integer not greater than N.

Examples

Input

100


Output

18


Input

9995


Output

35


Input

3141592653589793


Output

137

### Response

```cpp
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

int main(){
    string s;   cin >> s;
    int sum=0;
    for(int i=0; i<s.size(); i++)
        sum += s[i]-'0';
    sum = max(sum, (s[0]-'0'-1)+9*(int)(s.size()-1));
    cout << sum << endl;
}
    

```