#include<cstdio>
#include<algorithm>
using namespace std;
char s[20];

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

### Prompt

Generate a CPP solution 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<cstdio>
#include<algorithm>
using namespace std;
char s[20];

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

```