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

Develop a solution in cpp to the problem described below:

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>
inline long long read();
using namespace std;
int main()
{
    string s;cin>>s;
    int ans=0;
    for(int i=0;i<s.length();i++)
    {
        ans+=s[i]-'0';
    }
    ans=max(ans,(int)(s.length()-1)*9+s[0]-'1');
    cout<<ans;
}
```