#include<bits/stdc++.h>
using namespace std;
long long n;
int sum,sw,w;
int dsm(long long a){
	int sum=0;
	while(a){
		sum+=a%10;
		if(a<10) sw=a;
		a/=10,w++;
	}
	return sum;
}
int main(){
	scanf("%lld",&n);
	sum=dsm(n);
	printf("%d\n",max(sum,sw+w*9-10));
	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>
using namespace std;
long long n;
int sum,sw,w;
int dsm(long long a){
	int sum=0;
	while(a){
		sum+=a%10;
		if(a<10) sw=a;
		a/=10,w++;
	}
	return sum;
}
int main(){
	scanf("%lld",&n);
	sum=dsm(n);
	printf("%d\n",max(sum,sw+w*9-10));
	return 0;
}
```