#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;

char s[30];
int len;
int ans;

int main(){
	scanf("%s",s);
	len=strlen(s);
	ans=s[0]-'0'-1+9*(len-1);
	int sum=0;
	for(int i=0;i<len;i++)
		sum+=s[i]-'0';
	printf("%d\n",max(ans,sum));
	return 0;
}
### Prompt

Construct a cpp code solution to the problem outlined:

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>
#include<algorithm>
using namespace std;

char s[30];
int len;
int ans;

int main(){
	scanf("%s",s);
	len=strlen(s);
	ans=s[0]-'0'-1+9*(len-1);
	int sum=0;
	for(int i=0;i<len;i++)
		sum+=s[i]-'0';
	printf("%d\n",max(ans,sum));
	return 0;
}
```