#include<bits/stdc++.h>
using namespace std;

long long n, k, l=0, a[20], ans=0;


int main(){

cin >> n;
while(n>0){
    k=n%10;
    n/=10;
    ans+=k;
    a[l++]=k;
}

ans = max(ans, (l-1)*9 + a[l-1]-1);
cout << ans << endl;


return 0;}

### Prompt

Create a solution in cpp for 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;

long long n, k, l=0, a[20], ans=0;


int main(){

cin >> n;
while(n>0){
    k=n%10;
    n/=10;
    ans+=k;
    a[l++]=k;
}

ans = max(ans, (l-1)*9 + a[l-1]-1);
cout << ans << endl;


return 0;}

```