#include<bits/stdc++.h>
using namespace std;
int temp=0,temp1=0;
int main()
 {  string a;cin>>a;
    temp=a[0]-'0'-1;
    temp+=a.size()*9-9;
    for(int i=0;i<a.size();i++)
    temp1+=a[i]-'0';
    int final=max(temp1,temp);
    printf("%d\n",final);
}

### Prompt

Your task is to create 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<bits/stdc++.h>
using namespace std;
int temp=0,temp1=0;
int main()
 {  string a;cin>>a;
    temp=a[0]-'0'-1;
    temp+=a.size()*9-9;
    for(int i=0;i<a.size();i++)
    temp1+=a[i]-'0';
    int final=max(temp1,temp);
    printf("%d\n",final);
}

```