#include <iostream>
using namespace std;
string s;
int main()
{
	cin>>s;
	int len=s.length();
	long long ans;
	long long ano=0;
		ans = 9*(len-1);
		ans+=s[0]-'0'-1;
	for(int i=0;i<len;i++)
	{
		ano+=s[i]-'0';
	}
	cout<<max(ans,ano);
	return 0;
}

### Prompt

Develop a solution in cpp 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 <iostream>
using namespace std;
string s;
int main()
{
	cin>>s;
	int len=s.length();
	long long ans;
	long long ano=0;
		ans = 9*(len-1);
		ans+=s[0]-'0'-1;
	for(int i=0;i<len;i++)
	{
		ano+=s[i]-'0';
	}
	cout<<max(ans,ano);
	return 0;
}

```