#include <iostream>
#include <string>
#include <iomanip>
using namespace std;
int main(){
string s;cin>>s;
int n=s.length();
int c=0;
for(int i=1;i<n;i++){
if(s[i]!='9')c=1;}
int p=s[0]-'1';
if(c) cout<<p+9*(n-1);
else cout<<p+1+9*(n-1);
cout<<endl;}
### Prompt

Your challenge is to write 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 <iostream>
#include <string>
#include <iomanip>
using namespace std;
int main(){
string s;cin>>s;
int n=s.length();
int c=0;
for(int i=1;i<n;i++){
if(s[i]!='9')c=1;}
int p=s[0]-'1';
if(c) cout<<p+9*(n-1);
else cout<<p+1+9*(n-1);
cout<<endl;}
```