#include<bits/stdc++.h>
using namespace std;
int main()
{
	char n[20];
	int flag=1,i;
	scanf("%s",n);
	for(i=1;i<strlen(n);i++)
	{
		if(n[i]!='9')
			flag=0;
	}
	printf("%d",(strlen(n)-1)*9+(flag?n[0]-'0':n[0]-'1'));
	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<bits/stdc++.h>
using namespace std;
int main()
{
	char n[20];
	int flag=1,i;
	scanf("%s",n);
	for(i=1;i<strlen(n);i++)
	{
		if(n[i]!='9')
			flag=0;
	}
	printf("%d",(strlen(n)-1)*9+(flag?n[0]-'0':n[0]-'1'));
	return 0;
} 
```