#include<bits/stdc++.h>
using namespace std;
char s[2333];int len,ans;
int main()
{
	scanf("%s",s+1);len=strlen(s+1);
	ans=s[1]-'0'+(len-1)*9;
	for(int i=2;i<=len;++i)
	{
		if(s[i]!='9')
		{
			--ans;
			break;
		}
	}
	printf("%d",ans);
	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>
using namespace std;
char s[2333];int len,ans;
int main()
{
	scanf("%s",s+1);len=strlen(s+1);
	ans=s[1]-'0'+(len-1)*9;
	for(int i=2;i<=len;++i)
	{
		if(s[i]!='9')
		{
			--ans;
			break;
		}
	}
	printf("%d",ans);
	return 0;
}
```