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