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

In cpp, your task is to solve 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>
char s[100];
int ans,flag;
int main()
{
	scanf("%s",s);
	ans=9*(strlen(s)-1)+s[0]-'0'-1;
	flag=1;
	for (int i=1;i<strlen(s);i++) if (s[i]!='9') flag=0;
	printf("%d\n",ans+flag);
	return 0;
}
```