#include<bits/stdc++.h>
using namespace std;
signed main(){
  int b=0,c=1,d,e,f,g;
  string a;
  cin>>a;
  for(int i=0;i<a.size();i++){
    if(i==0) b+=a[i]-'0'-1;
    else b+=9;
    if(i!=0) if(a[i]!='9') c=0;
  }
  if(c) b++;
  cout<<b<<"\n";
  }

### 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;
signed main(){
  int b=0,c=1,d,e,f,g;
  string a;
  cin>>a;
  for(int i=0;i<a.size();i++){
    if(i==0) b+=a[i]-'0'-1;
    else b+=9;
    if(i!=0) if(a[i]!='9') c=0;
  }
  if(c) b++;
  cout<<b<<"\n";
  }

```