#include<bits/stdc++.h>

using namespace std;

char s[30];
int n,ans;
bool f;

int main()
{
    scanf("%s",s); n=strlen(s); f=true;
    ans=s[0]-'0'+(n-1)*9;
    for (int i=1;i<n;i++) if (s[i]!='9') f=false;
    if (!f) ans--;
    cout << ans << endl;
}

### 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;

char s[30];
int n,ans;
bool f;

int main()
{
    scanf("%s",s); n=strlen(s); f=true;
    ans=s[0]-'0'+(n-1)*9;
    for (int i=1;i<n;i++) if (s[i]!='9') f=false;
    if (!f) ans--;
    cout << ans << endl;
}

```