#include<bits/stdc++.h>
using namespace std;

int main(){
	long long a;
	scanf("%lld",&a);
	int tot=0;
	int flag=true;
	while(a>=10){
		tot+=9;
		if(a%10!=9)flag=false;
		a/=10;
	}
	if(flag==true)tot+=a;
	else
	tot+=a-1;
	printf("%d\n",tot);
}

//99989
//59992
### Prompt

Your task is to create 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 main(){
	long long a;
	scanf("%lld",&a);
	int tot=0;
	int flag=true;
	while(a>=10){
		tot+=9;
		if(a%10!=9)flag=false;
		a/=10;
	}
	if(flag==true)tot+=a;
	else
	tot+=a-1;
	printf("%d\n",tot);
}

//99989
//59992
```