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

int main(){
    string s;
    cin >> s;
    int ans1 = 0;
    for(int i=0;i<s.size();i++){
        ans1 += s[i] - '0';
    }

    int ans2 = s[0]-'1' +(s.size()-1)*9;
    cout << max(ans1,ans2) << endl;
}

### Prompt

In cpp, your task is to solve 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<iostream>
#include<algorithm>
#include<vector>
using namespace std;

int main(){
    string s;
    cin >> s;
    int ans1 = 0;
    for(int i=0;i<s.size();i++){
        ans1 += s[i] - '0';
    }

    int ans2 = s[0]-'1' +(s.size()-1)*9;
    cout << max(ans1,ans2) << endl;
}

```