#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <math.h>
using namespace std;

long long N, Ans;

int main() {
	scanf("%lld", &N);
	for(++N; N > 9; N /= 10) Ans += 9;
	printf("%lld\n", Ans + N - 1);
	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 <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <math.h>
using namespace std;

long long N, Ans;

int main() {
	scanf("%lld", &N);
	for(++N; N > 9; N /= 10) Ans += 9;
	printf("%lld\n", Ans + N - 1);
	return 0;
}
```