#include <bits/stdc++.h>
using namespace std;
int lA,ans;char a[25];bool fl=1;
int main()
{
	scanf("%s",a+1);lA=strlen(a+1);ans=9*(lA-1)+(a[1]&15)-1;
	for(int i=2;i<=lA;++i) if(a[i]!='9') {fl=0;break;}printf("%d\n",ans+fl);
}
### Prompt

Your challenge is to write 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 <bits/stdc++.h>
using namespace std;
int lA,ans;char a[25];bool fl=1;
int main()
{
	scanf("%s",a+1);lA=strlen(a+1);ans=9*(lA-1)+(a[1]&15)-1;
	for(int i=2;i<=lA;++i) if(a[i]!='9') {fl=0;break;}printf("%d\n",ans+fl);
}
```