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

#define int long long

int32_t main() {
	string s ;
	cin >> s ;
	int cnt = 0 ;
	for(auto i : s){
		cnt += (i-'0') ;
	}
	int l = s.size() ;
	cout << max(cnt , (9*(l-1) + (s[0]-'0'-1))) ;
	
	return 0;
}
### Prompt

Create a solution in CPP for 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;

#define int long long

int32_t main() {
	string s ;
	cin >> s ;
	int cnt = 0 ;
	for(auto i : s){
		cnt += (i-'0') ;
	}
	int l = s.size() ;
	cout << max(cnt , (9*(l-1) + (s[0]-'0'-1))) ;
	
	return 0;
}
```