#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
// 条件を見落としていませんか？
int main () {
    string N;
    cin >> N;
    ll ans = 0;
    for (auto x: N) ans += x-'0';
    cout << max((N[0]-'0'-1)+(ll)(N.size()-1)*9, ans) << endl;
}
### Prompt

Construct a CPP code solution to the problem outlined:

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;
// 条件を見落としていませんか？
int main () {
    string N;
    cin >> N;
    ll ans = 0;
    for (auto x: N) ans += x-'0';
    cout << max((N[0]-'0'-1)+(ll)(N.size()-1)*9, ans) << endl;
}
```