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

int main(){
	int a=0;
	string s;
	cin>>s;
	for(int i=1;i<s.size();i++){
		if(s[i]!='9'){
			a=9*(s.size()-1);
			a+=s[0]-'1';
			cout<<a;
			return 0;
		}
	}
	for(int i=0;i<s.size();i++) a+=s[i]-'0';
	cout<<a;
}

### Prompt

Generate 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(){
	int a=0;
	string s;
	cin>>s;
	for(int i=1;i<s.size();i++){
		if(s[i]!='9'){
			a=9*(s.size()-1);
			a+=s[0]-'1';
			cout<<a;
			return 0;
		}
	}
	for(int i=0;i<s.size();i++) a+=s[i]-'0';
	cout<<a;
}

```