#include <bits/stdc++.h>
using namespace std;
int main() {
	char a[110];
	scanf("%s", a + 1);
	int n = strlen(a + 1);
	int pp = 0;
	for(int i = 2; i <= n; i++)
		if(a[i] != '9') 
			pp = 1;
	cout << a[1] - '0' - pp + (n - 1) * 9;
	return 0;
}
### Prompt

Please create a solution in Cpp 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() {
	char a[110];
	scanf("%s", a + 1);
	int n = strlen(a + 1);
	int pp = 0;
	for(int i = 2; i <= n; i++)
		if(a[i] != '9') 
			pp = 1;
	cout << a[1] - '0' - pp + (n - 1) * 9;
	return 0;
}
```