#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cmath>
using namespace std;
char s[20];
int main() {
    scanf("%s",s);
    int n=strlen(s),flg=0;
    for(int i=1;i<n;i++) if(s[i]!='9') flg=1;
    cout<<s[0]-'0'-flg+9*(n-1);
    return 0;
}
### Prompt

Please create a solution in cpp 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 <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cmath>
using namespace std;
char s[20];
int main() {
    scanf("%s",s);
    int n=strlen(s),flg=0;
    for(int i=1;i<n;i++) if(s[i]!='9') flg=1;
    cout<<s[0]-'0'-flg+9*(n-1);
    return 0;
}
```