#include <bits/stdc++.h>
using namespace std;
int main()
{
    string S; cin >> S;
    int a = 0, b = 0;
    for (int i = 0; i < S.size(); i++) {
        a += S[i] - '0';
        b += i == 0 ? S[i]-'0'-1 : 9;
    }
    cout << max(a, b) << endl;
    return 0;
}

### Prompt

Please provide a CPP coded solution to the problem described below:

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 a = 0, b = 0;
    for (int i = 0; i < S.size(); i++) {
        a += S[i] - '0';
        b += i == 0 ? S[i]-'0'-1 : 9;
    }
    cout << max(a, b) << endl;
    return 0;
}

```