#include <bits/stdc++.h>

#define rep(i,n) for(int i=0;i<(n);i++)

using namespace std;

int main(){
	string str; 
  	cin>>str;

	int sum=0;
	for(char c:str) 
      sum+=c-'0';
	cout<<max<int>(sum,(str[0]-'1')+9*(str.length()-1))<<'\n';

	return 0;
}

### Prompt

Construct a CPP code solution to the problem outlined:

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>

#define rep(i,n) for(int i=0;i<(n);i++)

using namespace std;

int main(){
	string str; 
  	cin>>str;

	int sum=0;
	for(char c:str) 
      sum+=c-'0';
	cout<<max<int>(sum,(str[0]-'1')+9*(str.length()-1))<<'\n';

	return 0;
}

```