#include <bits/stdc++.h>  
#define ll long long
using namespace std;  
#define N 100005  
int main ()
{
	ll n,num = 0,ans = 0,mm = 0;
	cin >> n;
	while(n)
	{
		ans += n%10ll;
		mm = n%10ll;
		n/=10ll;
		num++; 
	}
	ans = max(ans,(num-1)*9+mm-1);
	cout << ans << endl;
	return 0;
}
### Prompt

Please formulate 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 ll long long
using namespace std;  
#define N 100005  
int main ()
{
	ll n,num = 0,ans = 0,mm = 0;
	cin >> n;
	while(n)
	{
		ans += n%10ll;
		mm = n%10ll;
		n/=10ll;
		num++; 
	}
	ans = max(ans,(num-1)*9+mm-1);
	cout << ans << endl;
	return 0;
}
```