#include<bits/stdc++.h>
int main()
{
	long long n;
	int cnt=0;
	bool lag = true;
	scanf("%lld",&n);
	while(n && n>9)
	{
		if(n%10 != 9)
			lag = false;
		n /= 10;
		cnt++;
	}
	printf("%d",lag ? cnt*9+n : cnt*9+n-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>
int main()
{
	long long n;
	int cnt=0;
	bool lag = true;
	scanf("%lld",&n);
	while(n && n>9)
	{
		if(n%10 != 9)
			lag = false;
		n /= 10;
		cnt++;
	}
	printf("%d",lag ? cnt*9+n : cnt*9+n-1);
	return 0;
 } 
```