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

int main()
{
//	freopen("input.txt","r",stdin);
	string s;
	cin>>s;
	int ans=0;
	int sum=s[0]-'0';
	ans+=s[0]-'0'-1;
	for (int i=1;i<s.length();i++)
	 {
	 	ans+=9;
	 	sum+=s[i]-'0';
	 }
	cout<<max(ans,sum)<<"\n";
}
### Prompt

Please formulate 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()
{
//	freopen("input.txt","r",stdin);
	string s;
	cin>>s;
	int ans=0;
	int sum=s[0]-'0';
	ans+=s[0]-'0'-1;
	for (int i=1;i<s.length();i++)
	 {
	 	ans+=9;
	 	sum+=s[i]-'0';
	 }
	cout<<max(ans,sum)<<"\n";
}
```