#include<cstdio>
#include<cstring>
using namespace std;
 
int main()
{
   	char a[100];
	int ans;
	scanf("%s",a);
	if(strlen(a)==1) ans=a[0]-'0';
	else if ( a[strlen(a)-1]=='9') ans=(strlen(a)-1)*9+a[0]-'0';
		else ans=(strlen(a)-1)*9+a[0]-'0'-1;
	printf("%d\n",ans);
   return 0;
}
### Prompt

Please create a solution in CPP 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<cstdio>
#include<cstring>
using namespace std;
 
int main()
{
   	char a[100];
	int ans;
	scanf("%s",a);
	if(strlen(a)==1) ans=a[0]-'0';
	else if ( a[strlen(a)-1]=='9') ans=(strlen(a)-1)*9+a[0]-'0';
		else ans=(strlen(a)-1)*9+a[0]-'0'-1;
	printf("%d\n",ans);
   return 0;
}
```