#include<cstdio>
using namespace std;
typedef long long LL;
LL n,num=1;
int ans1,ans2;
int main()
{
	scanf("%lld",&n);
	for(LL x=n;x;x/=10) ans1+=x%10,num*=10;
	num/=10;
	for(LL x=n/num*num-1;x;x/=10) ans2+=x%10;
	printf("%d",ans1>ans2?ans1:ans2);
	return 0;
}
### Prompt

Generate 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>
using namespace std;
typedef long long LL;
LL n,num=1;
int ans1,ans2;
int main()
{
	scanf("%lld",&n);
	for(LL x=n;x;x/=10) ans1+=x%10,num*=10;
	num/=10;
	for(LL x=n/num*num-1;x;x/=10) ans2+=x%10;
	printf("%d",ans1>ans2?ans1:ans2);
	return 0;
}
```