#include <bits/stdc++.h>
using namespace std;

int main()
{
    string s; cin>>s;
    int res=0, x=0;
    int n=s.size();
    for(int i=0; i<n; ++i) {
        res=max(x+s[i]-'1'+9*(n-1-i), res);
        x+=s[i]-'0';
    }
    res=max(res, x);
    cout<<res<<endl;
}

### 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 <bits/stdc++.h>
using namespace std;

int main()
{
    string s; cin>>s;
    int res=0, x=0;
    int n=s.size();
    for(int i=0; i<n; ++i) {
        res=max(x+s[i]-'1'+9*(n-1-i), res);
        x+=s[i]-'0';
    }
    res=max(res, x);
    cout<<res<<endl;
}

```