#include<bits/stdc++.h>
using namespace std;
char str[50];
int n;
int a,b;
int main()
{
	scanf("%s",&str);
	n=strlen(str);
	a=9*(n-1)+str[0]-'0'-1;
	for(int i=0;i<n;i++)
	b+=str[i]-'0';
	printf("%d",max(a,b));
	return 0;
}
### Prompt

Create a solution in Cpp for 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 str[50];
int n;
int a,b;
int main()
{
	scanf("%s",&str);
	n=strlen(str);
	a=9*(n-1)+str[0]-'0'-1;
	for(int i=0;i<n;i++)
	b+=str[i]-'0';
	printf("%d",max(a,b));
	return 0;
}
```