#include <bits/stdc++.h>
using namespace std;
char s[20];
int i,n,x,y;
 
int main()
{
	scanf("%s",s+1);
	n=strlen(s+1);
	for (i=1;i<=n;i++)
	{
		x+=s[i]-48;
	}
	y=s[1]-49+(n-1)*9;
	if(x>y)
	{
		printf("%d",x);
	}
	else
	{
		printf("%d",y);
	}
}
### 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 <bits/stdc++.h>
using namespace std;
char s[20];
int i,n,x,y;
 
int main()
{
	scanf("%s",s+1);
	n=strlen(s+1);
	for (i=1;i<=n;i++)
	{
		x+=s[i]-48;
	}
	y=s[1]-49+(n-1)*9;
	if(x>y)
	{
		printf("%d",x);
	}
	else
	{
		printf("%d",y);
	}
}
```