#include<bits/stdc++.h>
using namespace std;
char s[100];
int main() {
	scanf("%s", s);
	int ans = 0;
	for (int i = 0; s[i]; ++i) ans += s[i] - '0';
	ans = max(ans, int(s[0] - '1' + strlen(s + 1) * 9));
	printf("%d\n", ans);
	return 0;
}

### 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;
char s[100];
int main() {
	scanf("%s", s);
	int ans = 0;
	for (int i = 0; s[i]; ++i) ans += s[i] - '0';
	ans = max(ans, int(s[0] - '1' + strlen(s + 1) * 9));
	printf("%d\n", ans);
	return 0;
}

```