#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
char s[20];
int main(){
	scanf("%s", s);
	int l = strlen(s);
	LL ans = 0;
	for(int i=0;i<l;i++) ans += s[i]-'0';
	ans = max(ans, (s[0]-'0'-1)+9LL*(l-1));
	printf("%lld\n", ans);
}
### 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;
typedef long long LL;
char s[20];
int main(){
	scanf("%s", s);
	int l = strlen(s);
	LL ans = 0;
	for(int i=0;i<l;i++) ans += s[i]-'0';
	ans = max(ans, (s[0]-'0'-1)+9LL*(l-1));
	printf("%lld\n", ans);
}
```