#include<cstdio>
#include<algorithm>
using namespace std;

long long n;

int main(void) {
  scanf("%lld", &n);
  int ans = 0, u = 0, w = 0;
  while(n) {
    ans += n % 10;
    w = n % 10;
    n /= 10;
    u++;
  }
  printf("%d\n", max(ans, (u - 1) * 9 + w - 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<cstdio>
#include<algorithm>
using namespace std;

long long n;

int main(void) {
  scanf("%lld", &n);
  int ans = 0, u = 0, w = 0;
  while(n) {
    ans += n % 10;
    w = n % 10;
    n /= 10;
    u++;
  }
  printf("%d\n", max(ans, (u - 1) * 9 + w - 1));
  return 0;
}

```