#include<bits/stdc++.h>
using namespace std;
int main(){
    string S;cin>>S;
    int ans=0;
    for(int i=0;i<S.size();i++){
        ans+=S[i]-'0';
    }
    ans=max(ans,(int)((S[0]-'1')+9*S.size()-9));
    cout<<ans<<endl;
    return 0;
}
### Prompt

Generate a CPP solution 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;
int main(){
    string S;cin>>S;
    int ans=0;
    for(int i=0;i<S.size();i++){
        ans+=S[i]-'0';
    }
    ans=max(ans,(int)((S[0]-'1')+9*S.size()-9));
    cout<<ans<<endl;
    return 0;
}
```