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

char num[25];

int main()
{
	scanf("%s",num);
	int len=strlen(num);
	int ans=(len-1)*9+num[0]-'0';
	for(int i=1;i<len;i++)
	{
		if(num[i]!='9')
		{
			ans--;
			break;
		}
	}
	printf("%d",ans);
}
### 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;

char num[25];

int main()
{
	scanf("%s",num);
	int len=strlen(num);
	int ans=(len-1)*9+num[0]-'0';
	for(int i=1;i<len;i++)
	{
		if(num[i]!='9')
		{
			ans--;
			break;
		}
	}
	printf("%d",ans);
}
```