#include<bits/stdc++.h>
using namespace std;

int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	string s;
	cin>>s;
	int sum=0;
	for(auto it:s)
		sum+=it-'0';
	int sum2=s[0]-'1'+(s.size()-1)*9;
	cout<<max(sum,sum2)<<endl;
}

### Prompt

Please provide a cpp coded solution 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>
using namespace std;

int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	string s;
	cin>>s;
	int sum=0;
	for(auto it:s)
		sum+=it-'0';
	int sum2=s[0]-'1'+(s.size()-1)*9;
	cout<<max(sum,sum2)<<endl;
}

```