#include<bits/stdc++.h>
using namespace std;
signed main(){
	string s;cin>>s;
	int len=s.size();
	bool flag=1;
	for(register int i=1;i<len;i++)
		if(s[i]!='9'){
			flag=0;
			break;
		}
	printf("%d\n",(len-1)*9+s[0]-'0'-1+flag);
	return 0;
}
### 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>
using namespace std;
signed main(){
	string s;cin>>s;
	int len=s.size();
	bool flag=1;
	for(register int i=1;i<len;i++)
		if(s[i]!='9'){
			flag=0;
			break;
		}
	printf("%d\n",(len-1)*9+s[0]-'0'-1+flag);
	return 0;
}
```