#include<cstdio>
#include<algorithm>
using namespace std;
long long n,ans,a[20],cnt,sum;
int main()
{
	scanf("%lld",&n);
	while(n)
	{
		a[++cnt]=n%10;
		n/=10;
		sum+=a[cnt];
	}
	int ans=9*(cnt-1)+a[cnt]-1;
	if(sum>ans) ans=sum;
	printf("%lld",ans);
}
### Prompt

Please formulate 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<cstdio>
#include<algorithm>
using namespace std;
long long n,ans,a[20],cnt,sum;
int main()
{
	scanf("%lld",&n);
	while(n)
	{
		a[++cnt]=n%10;
		n/=10;
		sum+=a[cnt];
	}
	int ans=9*(cnt-1)+a[cnt]-1;
	if(sum>ans) ans=sum;
	printf("%lld",ans);
}
```