#include<iostream>
using namespace std;
typedef long long int LL;
int main(){
	LL n;
	int i,j,k;
	int s;
	bool g=true;
	cin>>n;
	for(i=0;n>=10;n/=10){
		if(n%10!=9)g=false;
		i++;
	}
	s=i*9+n;
	if(!g)s--;
	cout<<s<<endl;
	return 0;
}

### Prompt

Please provide a CPP coded solution to the problem described below:

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<iostream>
using namespace std;
typedef long long int LL;
int main(){
	LL n;
	int i,j,k;
	int s;
	bool g=true;
	cin>>n;
	for(i=0;n>=10;n/=10){
		if(n%10!=9)g=false;
		i++;
	}
	s=i*9+n;
	if(!g)s--;
	cout<<s<<endl;
	return 0;
}

```