#include<bits/stdc++.h>
using namespace std;
long long N;
int main(){
	cin>>N;
	int l=1;int F=1;
	while(N/10!=0){++l;if(N%10!=9)F=0;N/=10;}
	cout<<(l-1)*9+N-1+F;
	return 0;
}

### Prompt

Please create a solution in Cpp 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;
long long N;
int main(){
	cin>>N;
	int l=1;int F=1;
	while(N/10!=0){++l;if(N%10!=9)F=0;N/=10;}
	cout<<(l-1)*9+N-1+F;
	return 0;
}

```