#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

string n;

int main(){
    cin >> n;
    int c = n.size();
    int d = 0;
    for(auto i : n) d += i - '0';
    cout << max(d, (c - 1) * 9 + n[0] - '0' - 1);
}

### Prompt

Your challenge is to write 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;

typedef long long ll;

string n;

int main(){
    cin >> n;
    int c = n.size();
    int d = 0;
    for(auto i : n) d += i - '0';
    cout << max(d, (c - 1) * 9 + n[0] - '0' - 1);
}

```