#include<stdio.h>
#include<string.h>
int main()
{
	char s[1000];
	scanf(" %s", s);
	int l = strlen(s);
	int a, b=0, c;
	a = (s[0] - 49) + 9 * (l - 1);
	for (int i = 0;i < l;i++)
		b += (s[i]-48);
	c = a > b ? a : b;
	printf("%d", c);
}
### Prompt

In cpp, your task is to solve 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<stdio.h>
#include<string.h>
int main()
{
	char s[1000];
	scanf(" %s", s);
	int l = strlen(s);
	int a, b=0, c;
	a = (s[0] - 49) + 9 * (l - 1);
	for (int i = 0;i < l;i++)
		b += (s[i]-48);
	c = a > b ? a : b;
	printf("%d", c);
}
```