#include <bits/stdc++.h>
//#define MAXN 
using namespace std;
char str[20];
int len,ans,ch;

int main()
{
	cin>>str;
	len=strlen(str);
	ans=str[0]-'0';
	for(int i=1; i<len; i++)
		if(str[i]!='9') ch=1;
	if(ch && len!=1) ans-=1;
	printf("%d\n",(len-1)*9+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 <bits/stdc++.h>
//#define MAXN 
using namespace std;
char str[20];
int len,ans,ch;

int main()
{
	cin>>str;
	len=strlen(str);
	ans=str[0]-'0';
	for(int i=1; i<len; i++)
		if(str[i]!='9') ch=1;
	if(ch && len!=1) ans-=1;
	printf("%d\n",(len-1)*9+ans);
	return 0;
}
```