#include <bits/stdc++.h>
#define pi 3.14159
using namespace std;
int main(){
	string n;
	cin >> n;
	int a=0;
	for(int i=0;i<n.size();i++){
		a+=(n[i]-'0');
	}
	int m=((int)n[0]-(int)'0'-1)+((n.size()-1)*9);
	cout << max(a,m);
}
### 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>
#define pi 3.14159
using namespace std;
int main(){
	string n;
	cin >> n;
	int a=0;
	for(int i=0;i<n.size();i++){
		a+=(n[i]-'0');
	}
	int m=((int)n[0]-(int)'0'-1)+((n.size()-1)*9);
	cout << max(a,m);
}
```