#include <bits/stdc++.h>
using namespace std;
char s[22];
int n;
int main()
{
    scanf("%s",s+1);
    n=strlen(s+1);
    int sum=0;
    for(int i=1;i<=n;i++) sum+=s[i]-'0';
    printf("%d\n",max(sum,(n-1)*9+s[1]-'0'-1));
    return 0;
}

### Prompt

In CPP, your task is to solve 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;
char s[22];
int n;
int main()
{
    scanf("%s",s+1);
    n=strlen(s+1);
    int sum=0;
    for(int i=1;i<=n;i++) sum+=s[i]-'0';
    printf("%d\n",max(sum,(n-1)*9+s[1]-'0'-1));
    return 0;
}

```