#include<bits/stdc++.h>
using namespace std;
int main(){
	char str[20];
	scanf("%s",str);
	int ans = 0;
	int len = strlen(str);
	for(int i=0;i<len;i++)
		ans +=str[i]-'0';
	int sum = str[0]-'0'-1+9*(len-1);
	printf("%d\n",max(sum,ans));
	return 0;
} 
### Prompt

Your task is to create 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;
int main(){
	char str[20];
	scanf("%s",str);
	int ans = 0;
	int len = strlen(str);
	for(int i=0;i<len;i++)
		ans +=str[i]-'0';
	int sum = str[0]-'0'-1+9*(len-1);
	printf("%d\n",max(sum,ans));
	return 0;
} 
```